1 // SPDX-License-Identifier: GPL-2.0
3 * Block multiqueue core code
5 * Copyright (C) 2013-2014 Jens Axboe
6 * Copyright (C) 2013-2014 Christoph Hellwig
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/backing-dev.h>
11 #include <linux/bio.h>
12 #include <linux/blkdev.h>
13 #include <linux/blk-integrity.h>
14 #include <linux/kmemleak.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/workqueue.h>
19 #include <linux/smp.h>
20 #include <linux/interrupt.h>
21 #include <linux/llist.h>
22 #include <linux/cpu.h>
23 #include <linux/cache.h>
24 #include <linux/sched/topology.h>
25 #include <linux/sched/signal.h>
26 #include <linux/delay.h>
27 #include <linux/crash_dump.h>
28 #include <linux/prefetch.h>
29 #include <linux/blk-crypto.h>
30 #include <linux/part_stat.h>
32 #include <trace/events/block.h>
34 #include <linux/t10-pi.h>
37 #include "blk-mq-debugfs.h"
40 #include "blk-mq-sched.h"
41 #include "blk-rq-qos.h"
43 static DEFINE_PER_CPU(struct llist_head, blk_cpu_done);
44 static DEFINE_PER_CPU(call_single_data_t, blk_cpu_csd);
46 static void blk_mq_insert_request(struct request *rq, blk_insert_t flags);
47 static void blk_mq_request_bypass_insert(struct request *rq,
49 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
50 struct list_head *list);
51 static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
52 struct io_comp_batch *iob, unsigned int flags);
55 * Check if any of the ctx, dispatch list or elevator
56 * have pending work in this hardware queue.
58 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
60 return !list_empty_careful(&hctx->dispatch) ||
61 sbitmap_any_bit_set(&hctx->ctx_map) ||
62 blk_mq_sched_has_work(hctx);
66 * Mark this ctx as having pending work in this hardware queue
68 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
69 struct blk_mq_ctx *ctx)
71 const int bit = ctx->index_hw[hctx->type];
73 if (!sbitmap_test_bit(&hctx->ctx_map, bit))
74 sbitmap_set_bit(&hctx->ctx_map, bit);
77 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
78 struct blk_mq_ctx *ctx)
80 const int bit = ctx->index_hw[hctx->type];
82 sbitmap_clear_bit(&hctx->ctx_map, bit);
86 struct block_device *part;
87 unsigned int inflight[2];
90 static bool blk_mq_check_inflight(struct request *rq, void *priv)
92 struct mq_inflight *mi = priv;
94 if (rq->part && blk_do_io_stat(rq) &&
95 (!mi->part->bd_partno || rq->part == mi->part) &&
96 blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT)
97 mi->inflight[rq_data_dir(rq)]++;
102 unsigned int blk_mq_in_flight(struct request_queue *q,
103 struct block_device *part)
105 struct mq_inflight mi = { .part = part };
107 blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
109 return mi.inflight[0] + mi.inflight[1];
112 void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
113 unsigned int inflight[2])
115 struct mq_inflight mi = { .part = part };
117 blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
118 inflight[0] = mi.inflight[0];
119 inflight[1] = mi.inflight[1];
122 void blk_freeze_queue_start(struct request_queue *q)
124 mutex_lock(&q->mq_freeze_lock);
125 if (++q->mq_freeze_depth == 1) {
126 percpu_ref_kill(&q->q_usage_counter);
127 mutex_unlock(&q->mq_freeze_lock);
129 blk_mq_run_hw_queues(q, false);
131 mutex_unlock(&q->mq_freeze_lock);
134 EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
136 void blk_mq_freeze_queue_wait(struct request_queue *q)
138 wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter));
140 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait);
142 int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
143 unsigned long timeout)
145 return wait_event_timeout(q->mq_freeze_wq,
146 percpu_ref_is_zero(&q->q_usage_counter),
149 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);
152 * Guarantee no request is in use, so we can change any data structure of
153 * the queue afterward.
155 void blk_freeze_queue(struct request_queue *q)
158 * In the !blk_mq case we are only calling this to kill the
159 * q_usage_counter, otherwise this increases the freeze depth
160 * and waits for it to return to zero. For this reason there is
161 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
162 * exported to drivers as the only user for unfreeze is blk_mq.
164 blk_freeze_queue_start(q);
165 blk_mq_freeze_queue_wait(q);
168 void blk_mq_freeze_queue(struct request_queue *q)
171 * ...just an alias to keep freeze and unfreeze actions balanced
172 * in the blk_mq_* namespace
176 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue);
178 void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic)
180 mutex_lock(&q->mq_freeze_lock);
182 q->q_usage_counter.data->force_atomic = true;
183 q->mq_freeze_depth--;
184 WARN_ON_ONCE(q->mq_freeze_depth < 0);
185 if (!q->mq_freeze_depth) {
186 percpu_ref_resurrect(&q->q_usage_counter);
187 wake_up_all(&q->mq_freeze_wq);
189 mutex_unlock(&q->mq_freeze_lock);
192 void blk_mq_unfreeze_queue(struct request_queue *q)
194 __blk_mq_unfreeze_queue(q, false);
196 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
199 * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
200 * mpt3sas driver such that this function can be removed.
202 void blk_mq_quiesce_queue_nowait(struct request_queue *q)
206 spin_lock_irqsave(&q->queue_lock, flags);
207 if (!q->quiesce_depth++)
208 blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q);
209 spin_unlock_irqrestore(&q->queue_lock, flags);
211 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait);
214 * blk_mq_wait_quiesce_done() - wait until in-progress quiesce is done
215 * @set: tag_set to wait on
217 * Note: it is driver's responsibility for making sure that quiesce has
218 * been started on or more of the request_queues of the tag_set. This
219 * function only waits for the quiesce on those request_queues that had
220 * the quiesce flag set using blk_mq_quiesce_queue_nowait.
222 void blk_mq_wait_quiesce_done(struct blk_mq_tag_set *set)
224 if (set->flags & BLK_MQ_F_BLOCKING)
225 synchronize_srcu(set->srcu);
229 EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done);
232 * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
235 * Note: this function does not prevent that the struct request end_io()
236 * callback function is invoked. Once this function is returned, we make
237 * sure no dispatch can happen until the queue is unquiesced via
238 * blk_mq_unquiesce_queue().
240 void blk_mq_quiesce_queue(struct request_queue *q)
242 blk_mq_quiesce_queue_nowait(q);
243 /* nothing to wait for non-mq queues */
245 blk_mq_wait_quiesce_done(q->tag_set);
247 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
250 * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
253 * This function recovers queue into the state before quiescing
254 * which is done by blk_mq_quiesce_queue.
256 void blk_mq_unquiesce_queue(struct request_queue *q)
259 bool run_queue = false;
261 spin_lock_irqsave(&q->queue_lock, flags);
262 if (WARN_ON_ONCE(q->quiesce_depth <= 0)) {
264 } else if (!--q->quiesce_depth) {
265 blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
268 spin_unlock_irqrestore(&q->queue_lock, flags);
270 /* dispatch requests which are inserted during quiescing */
272 blk_mq_run_hw_queues(q, true);
274 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
276 void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set)
278 struct request_queue *q;
280 mutex_lock(&set->tag_list_lock);
281 list_for_each_entry(q, &set->tag_list, tag_set_list) {
282 if (!blk_queue_skip_tagset_quiesce(q))
283 blk_mq_quiesce_queue_nowait(q);
285 blk_mq_wait_quiesce_done(set);
286 mutex_unlock(&set->tag_list_lock);
288 EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset);
290 void blk_mq_unquiesce_tagset(struct blk_mq_tag_set *set)
292 struct request_queue *q;
294 mutex_lock(&set->tag_list_lock);
295 list_for_each_entry(q, &set->tag_list, tag_set_list) {
296 if (!blk_queue_skip_tagset_quiesce(q))
297 blk_mq_unquiesce_queue(q);
299 mutex_unlock(&set->tag_list_lock);
301 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_tagset);
303 void blk_mq_wake_waiters(struct request_queue *q)
305 struct blk_mq_hw_ctx *hctx;
308 queue_for_each_hw_ctx(q, hctx, i)
309 if (blk_mq_hw_queue_mapped(hctx))
310 blk_mq_tag_wakeup_all(hctx->tags, true);
313 void blk_rq_init(struct request_queue *q, struct request *rq)
315 memset(rq, 0, sizeof(*rq));
317 INIT_LIST_HEAD(&rq->queuelist);
319 rq->__sector = (sector_t) -1;
320 INIT_HLIST_NODE(&rq->hash);
321 RB_CLEAR_NODE(&rq->rb_node);
322 rq->tag = BLK_MQ_NO_TAG;
323 rq->internal_tag = BLK_MQ_NO_TAG;
324 rq->start_time_ns = blk_time_get_ns();
326 blk_crypto_rq_set_defaults(rq);
328 EXPORT_SYMBOL(blk_rq_init);
330 /* Set start and alloc time when the allocated request is actually used */
331 static inline void blk_mq_rq_time_init(struct request *rq, u64 alloc_time_ns)
333 if (blk_mq_need_time_stamp(rq))
334 rq->start_time_ns = blk_time_get_ns();
336 rq->start_time_ns = 0;
338 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
339 if (blk_queue_rq_alloc_time(rq->q))
340 rq->alloc_time_ns = alloc_time_ns ?: rq->start_time_ns;
342 rq->alloc_time_ns = 0;
346 static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
347 struct blk_mq_tags *tags, unsigned int tag)
349 struct blk_mq_ctx *ctx = data->ctx;
350 struct blk_mq_hw_ctx *hctx = data->hctx;
351 struct request_queue *q = data->q;
352 struct request *rq = tags->static_rqs[tag];
357 rq->cmd_flags = data->cmd_flags;
359 if (data->flags & BLK_MQ_REQ_PM)
360 data->rq_flags |= RQF_PM;
361 if (blk_queue_io_stat(q))
362 data->rq_flags |= RQF_IO_STAT;
363 rq->rq_flags = data->rq_flags;
365 if (data->rq_flags & RQF_SCHED_TAGS) {
366 rq->tag = BLK_MQ_NO_TAG;
367 rq->internal_tag = tag;
370 rq->internal_tag = BLK_MQ_NO_TAG;
375 rq->io_start_time_ns = 0;
376 rq->stats_sectors = 0;
377 rq->nr_phys_segments = 0;
378 #if defined(CONFIG_BLK_DEV_INTEGRITY)
379 rq->nr_integrity_segments = 0;
382 rq->end_io_data = NULL;
384 blk_crypto_rq_set_defaults(rq);
385 INIT_LIST_HEAD(&rq->queuelist);
386 /* tag was already set */
387 WRITE_ONCE(rq->deadline, 0);
390 if (rq->rq_flags & RQF_USE_SCHED) {
391 struct elevator_queue *e = data->q->elevator;
393 INIT_HLIST_NODE(&rq->hash);
394 RB_CLEAR_NODE(&rq->rb_node);
396 if (e->type->ops.prepare_request)
397 e->type->ops.prepare_request(rq);
403 static inline struct request *
404 __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data)
406 unsigned int tag, tag_offset;
407 struct blk_mq_tags *tags;
409 unsigned long tag_mask;
412 tag_mask = blk_mq_get_tags(data, data->nr_tags, &tag_offset);
413 if (unlikely(!tag_mask))
416 tags = blk_mq_tags_from_data(data);
417 for (i = 0; tag_mask; i++) {
418 if (!(tag_mask & (1UL << i)))
420 tag = tag_offset + i;
421 prefetch(tags->static_rqs[tag]);
422 tag_mask &= ~(1UL << i);
423 rq = blk_mq_rq_ctx_init(data, tags, tag);
424 rq_list_add(data->cached_rq, rq);
427 if (!(data->rq_flags & RQF_SCHED_TAGS))
428 blk_mq_add_active_requests(data->hctx, nr);
429 /* caller already holds a reference, add for remainder */
430 percpu_ref_get_many(&data->q->q_usage_counter, nr - 1);
433 return rq_list_pop(data->cached_rq);
436 static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)
438 struct request_queue *q = data->q;
439 u64 alloc_time_ns = 0;
443 /* alloc_time includes depth and tag waits */
444 if (blk_queue_rq_alloc_time(q))
445 alloc_time_ns = blk_time_get_ns();
447 if (data->cmd_flags & REQ_NOWAIT)
448 data->flags |= BLK_MQ_REQ_NOWAIT;
452 * All requests use scheduler tags when an I/O scheduler is
453 * enabled for the queue.
455 data->rq_flags |= RQF_SCHED_TAGS;
458 * Flush/passthrough requests are special and go directly to the
461 if ((data->cmd_flags & REQ_OP_MASK) != REQ_OP_FLUSH &&
462 !blk_op_is_passthrough(data->cmd_flags)) {
463 struct elevator_mq_ops *ops = &q->elevator->type->ops;
465 WARN_ON_ONCE(data->flags & BLK_MQ_REQ_RESERVED);
467 data->rq_flags |= RQF_USE_SCHED;
468 if (ops->limit_depth)
469 ops->limit_depth(data->cmd_flags, data);
474 data->ctx = blk_mq_get_ctx(q);
475 data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx);
476 if (!(data->rq_flags & RQF_SCHED_TAGS))
477 blk_mq_tag_busy(data->hctx);
479 if (data->flags & BLK_MQ_REQ_RESERVED)
480 data->rq_flags |= RQF_RESV;
483 * Try batched alloc if we want more than 1 tag.
485 if (data->nr_tags > 1) {
486 rq = __blk_mq_alloc_requests_batch(data);
488 blk_mq_rq_time_init(rq, alloc_time_ns);
495 * Waiting allocations only fail because of an inactive hctx. In that
496 * case just retry the hctx assignment and tag allocation as CPU hotplug
497 * should have migrated us to an online CPU by now.
499 tag = blk_mq_get_tag(data);
500 if (tag == BLK_MQ_NO_TAG) {
501 if (data->flags & BLK_MQ_REQ_NOWAIT)
504 * Give up the CPU and sleep for a random short time to
505 * ensure that thread using a realtime scheduling class
506 * are migrated off the CPU, and thus off the hctx that
513 if (!(data->rq_flags & RQF_SCHED_TAGS))
514 blk_mq_inc_active_requests(data->hctx);
515 rq = blk_mq_rq_ctx_init(data, blk_mq_tags_from_data(data), tag);
516 blk_mq_rq_time_init(rq, alloc_time_ns);
520 static struct request *blk_mq_rq_cache_fill(struct request_queue *q,
521 struct blk_plug *plug,
523 blk_mq_req_flags_t flags)
525 struct blk_mq_alloc_data data = {
529 .nr_tags = plug->nr_ios,
530 .cached_rq = &plug->cached_rq,
534 if (blk_queue_enter(q, flags))
539 rq = __blk_mq_alloc_requests(&data);
545 static struct request *blk_mq_alloc_cached_request(struct request_queue *q,
547 blk_mq_req_flags_t flags)
549 struct blk_plug *plug = current->plug;
555 if (rq_list_empty(plug->cached_rq)) {
556 if (plug->nr_ios == 1)
558 rq = blk_mq_rq_cache_fill(q, plug, opf, flags);
562 rq = rq_list_peek(&plug->cached_rq);
563 if (!rq || rq->q != q)
566 if (blk_mq_get_hctx_type(opf) != rq->mq_hctx->type)
568 if (op_is_flush(rq->cmd_flags) != op_is_flush(opf))
571 plug->cached_rq = rq_list_next(rq);
572 blk_mq_rq_time_init(rq, 0);
576 INIT_LIST_HEAD(&rq->queuelist);
580 struct request *blk_mq_alloc_request(struct request_queue *q, blk_opf_t opf,
581 blk_mq_req_flags_t flags)
585 rq = blk_mq_alloc_cached_request(q, opf, flags);
587 struct blk_mq_alloc_data data = {
595 ret = blk_queue_enter(q, flags);
599 rq = __blk_mq_alloc_requests(&data);
604 rq->__sector = (sector_t) -1;
605 rq->bio = rq->biotail = NULL;
609 return ERR_PTR(-EWOULDBLOCK);
611 EXPORT_SYMBOL(blk_mq_alloc_request);
613 struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
614 blk_opf_t opf, blk_mq_req_flags_t flags, unsigned int hctx_idx)
616 struct blk_mq_alloc_data data = {
622 u64 alloc_time_ns = 0;
628 /* alloc_time includes depth and tag waits */
629 if (blk_queue_rq_alloc_time(q))
630 alloc_time_ns = blk_time_get_ns();
633 * If the tag allocator sleeps we could get an allocation for a
634 * different hardware context. No need to complicate the low level
635 * allocator for this for the rare use case of a command tied to
638 if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT)) ||
639 WARN_ON_ONCE(!(flags & BLK_MQ_REQ_RESERVED)))
640 return ERR_PTR(-EINVAL);
642 if (hctx_idx >= q->nr_hw_queues)
643 return ERR_PTR(-EIO);
645 ret = blk_queue_enter(q, flags);
650 * Check if the hardware context is actually mapped to anything.
651 * If not tell the caller that it should skip this queue.
654 data.hctx = xa_load(&q->hctx_table, hctx_idx);
655 if (!blk_mq_hw_queue_mapped(data.hctx))
657 cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask);
658 if (cpu >= nr_cpu_ids)
660 data.ctx = __blk_mq_get_ctx(q, cpu);
663 data.rq_flags |= RQF_SCHED_TAGS;
665 blk_mq_tag_busy(data.hctx);
667 if (flags & BLK_MQ_REQ_RESERVED)
668 data.rq_flags |= RQF_RESV;
671 tag = blk_mq_get_tag(&data);
672 if (tag == BLK_MQ_NO_TAG)
674 if (!(data.rq_flags & RQF_SCHED_TAGS))
675 blk_mq_inc_active_requests(data.hctx);
676 rq = blk_mq_rq_ctx_init(&data, blk_mq_tags_from_data(&data), tag);
677 blk_mq_rq_time_init(rq, alloc_time_ns);
679 rq->__sector = (sector_t) -1;
680 rq->bio = rq->biotail = NULL;
687 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
689 static void blk_mq_finish_request(struct request *rq)
691 struct request_queue *q = rq->q;
693 if (rq->rq_flags & RQF_USE_SCHED) {
694 q->elevator->type->ops.finish_request(rq);
696 * For postflush request that may need to be
697 * completed twice, we should clear this flag
698 * to avoid double finish_request() on the rq.
700 rq->rq_flags &= ~RQF_USE_SCHED;
704 static void __blk_mq_free_request(struct request *rq)
706 struct request_queue *q = rq->q;
707 struct blk_mq_ctx *ctx = rq->mq_ctx;
708 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
709 const int sched_tag = rq->internal_tag;
711 blk_crypto_free_request(rq);
712 blk_pm_mark_last_busy(rq);
715 if (rq->tag != BLK_MQ_NO_TAG) {
716 blk_mq_dec_active_requests(hctx);
717 blk_mq_put_tag(hctx->tags, ctx, rq->tag);
719 if (sched_tag != BLK_MQ_NO_TAG)
720 blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag);
721 blk_mq_sched_restart(hctx);
725 void blk_mq_free_request(struct request *rq)
727 struct request_queue *q = rq->q;
729 blk_mq_finish_request(rq);
731 if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
732 laptop_io_completion(q->disk->bdi);
736 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
737 if (req_ref_put_and_test(rq))
738 __blk_mq_free_request(rq);
740 EXPORT_SYMBOL_GPL(blk_mq_free_request);
742 void blk_mq_free_plug_rqs(struct blk_plug *plug)
746 while ((rq = rq_list_pop(&plug->cached_rq)) != NULL)
747 blk_mq_free_request(rq);
750 void blk_dump_rq_flags(struct request *rq, char *msg)
752 printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg,
753 rq->q->disk ? rq->q->disk->disk_name : "?",
754 (__force unsigned long long) rq->cmd_flags);
756 printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
757 (unsigned long long)blk_rq_pos(rq),
758 blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
759 printk(KERN_INFO " bio %p, biotail %p, len %u\n",
760 rq->bio, rq->biotail, blk_rq_bytes(rq));
762 EXPORT_SYMBOL(blk_dump_rq_flags);
764 static void req_bio_endio(struct request *rq, struct bio *bio,
765 unsigned int nbytes, blk_status_t error)
767 if (unlikely(error)) {
768 bio->bi_status = error;
769 } else if (req_op(rq) == REQ_OP_ZONE_APPEND) {
771 * Partial zone append completions cannot be supported as the
772 * BIO fragments may end up not being written sequentially.
774 if (bio->bi_iter.bi_size != nbytes)
775 bio->bi_status = BLK_STS_IOERR;
777 bio->bi_iter.bi_sector = rq->__sector;
780 bio_advance(bio, nbytes);
782 if (unlikely(rq->rq_flags & RQF_QUIET))
783 bio_set_flag(bio, BIO_QUIET);
784 /* don't actually finish bio if it's part of flush sequence */
785 if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
789 static void blk_account_io_completion(struct request *req, unsigned int bytes)
791 if (req->part && blk_do_io_stat(req)) {
792 const int sgrp = op_stat_group(req_op(req));
795 part_stat_add(req->part, sectors[sgrp], bytes >> 9);
800 static void blk_print_req_error(struct request *req, blk_status_t status)
802 printk_ratelimited(KERN_ERR
803 "%s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
804 "phys_seg %u prio class %u\n",
805 blk_status_to_str(status),
806 req->q->disk ? req->q->disk->disk_name : "?",
807 blk_rq_pos(req), (__force u32)req_op(req),
808 blk_op_str(req_op(req)),
809 (__force u32)(req->cmd_flags & ~REQ_OP_MASK),
810 req->nr_phys_segments,
811 IOPRIO_PRIO_CLASS(req->ioprio));
815 * Fully end IO on a request. Does not support partial completions, or
818 static void blk_complete_request(struct request *req)
820 const bool is_flush = (req->rq_flags & RQF_FLUSH_SEQ) != 0;
821 int total_bytes = blk_rq_bytes(req);
822 struct bio *bio = req->bio;
824 trace_block_rq_complete(req, BLK_STS_OK, total_bytes);
829 #ifdef CONFIG_BLK_DEV_INTEGRITY
830 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ)
831 req->q->integrity.profile->complete_fn(req, total_bytes);
835 * Upper layers may call blk_crypto_evict_key() anytime after the last
836 * bio_endio(). Therefore, the keyslot must be released before that.
838 blk_crypto_rq_put_keyslot(req);
840 blk_account_io_completion(req, total_bytes);
843 struct bio *next = bio->bi_next;
845 /* Completion has already been traced */
846 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
848 if (req_op(req) == REQ_OP_ZONE_APPEND)
849 bio->bi_iter.bi_sector = req->__sector;
857 * Reset counters so that the request stacking driver
858 * can find how many bytes remain in the request
868 * blk_update_request - Complete multiple bytes without completing the request
869 * @req: the request being processed
870 * @error: block status code
871 * @nr_bytes: number of bytes to complete for @req
874 * Ends I/O on a number of bytes attached to @req, but doesn't complete
875 * the request structure even if @req doesn't have leftover.
876 * If @req has leftover, sets it up for the next range of segments.
878 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
879 * %false return from this function.
882 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function
883 * except in the consistency check at the end of this function.
886 * %false - this request doesn't have any more data
887 * %true - this request has more data
889 bool blk_update_request(struct request *req, blk_status_t error,
890 unsigned int nr_bytes)
894 trace_block_rq_complete(req, error, nr_bytes);
899 #ifdef CONFIG_BLK_DEV_INTEGRITY
900 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ &&
902 req->q->integrity.profile->complete_fn(req, nr_bytes);
906 * Upper layers may call blk_crypto_evict_key() anytime after the last
907 * bio_endio(). Therefore, the keyslot must be released before that.
909 if (blk_crypto_rq_has_keyslot(req) && nr_bytes >= blk_rq_bytes(req))
910 __blk_crypto_rq_put_keyslot(req);
912 if (unlikely(error && !blk_rq_is_passthrough(req) &&
913 !(req->rq_flags & RQF_QUIET)) &&
914 !test_bit(GD_DEAD, &req->q->disk->state)) {
915 blk_print_req_error(req, error);
916 trace_block_rq_error(req, error, nr_bytes);
919 blk_account_io_completion(req, nr_bytes);
923 struct bio *bio = req->bio;
924 unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
926 if (bio_bytes == bio->bi_iter.bi_size)
927 req->bio = bio->bi_next;
929 /* Completion has already been traced */
930 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
931 req_bio_endio(req, bio, bio_bytes, error);
933 total_bytes += bio_bytes;
934 nr_bytes -= bio_bytes;
945 * Reset counters so that the request stacking driver
946 * can find how many bytes remain in the request
953 req->__data_len -= total_bytes;
955 /* update sector only for requests with clear definition of sector */
956 if (!blk_rq_is_passthrough(req))
957 req->__sector += total_bytes >> 9;
959 /* mixed attributes always follow the first bio */
960 if (req->rq_flags & RQF_MIXED_MERGE) {
961 req->cmd_flags &= ~REQ_FAILFAST_MASK;
962 req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK;
965 if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) {
967 * If total number of sectors is less than the first segment
968 * size, something has gone terribly wrong.
970 if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
971 blk_dump_rq_flags(req, "request botched");
972 req->__data_len = blk_rq_cur_bytes(req);
975 /* recalculate the number of segments */
976 req->nr_phys_segments = blk_recalc_rq_segments(req);
981 EXPORT_SYMBOL_GPL(blk_update_request);
983 static inline void blk_account_io_done(struct request *req, u64 now)
985 trace_block_io_done(req);
988 * Account IO completion. flush_rq isn't accounted as a
989 * normal IO on queueing nor completion. Accounting the
990 * containing request is enough.
992 if (blk_do_io_stat(req) && req->part &&
993 !(req->rq_flags & RQF_FLUSH_SEQ)) {
994 const int sgrp = op_stat_group(req_op(req));
997 update_io_ticks(req->part, jiffies, true);
998 part_stat_inc(req->part, ios[sgrp]);
999 part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
1004 static inline void blk_account_io_start(struct request *req)
1006 trace_block_io_start(req);
1008 if (blk_do_io_stat(req)) {
1010 * All non-passthrough requests are created from a bio with one
1011 * exception: when a flush command that is part of a flush sequence
1012 * generated by the state machine in blk-flush.c is cloned onto the
1013 * lower device by dm-multipath we can get here without a bio.
1016 req->part = req->bio->bi_bdev;
1018 req->part = req->q->disk->part0;
1021 update_io_ticks(req->part, jiffies, false);
1026 static inline void __blk_mq_end_request_acct(struct request *rq, u64 now)
1028 if (rq->rq_flags & RQF_STATS)
1029 blk_stat_add(rq, now);
1031 blk_mq_sched_completed_request(rq, now);
1032 blk_account_io_done(rq, now);
1035 inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
1037 if (blk_mq_need_time_stamp(rq))
1038 __blk_mq_end_request_acct(rq, blk_time_get_ns());
1040 blk_mq_finish_request(rq);
1043 rq_qos_done(rq->q, rq);
1044 if (rq->end_io(rq, error) == RQ_END_IO_FREE)
1045 blk_mq_free_request(rq);
1047 blk_mq_free_request(rq);
1050 EXPORT_SYMBOL(__blk_mq_end_request);
1052 void blk_mq_end_request(struct request *rq, blk_status_t error)
1054 if (blk_update_request(rq, error, blk_rq_bytes(rq)))
1056 __blk_mq_end_request(rq, error);
1058 EXPORT_SYMBOL(blk_mq_end_request);
1060 #define TAG_COMP_BATCH 32
1062 static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx *hctx,
1063 int *tag_array, int nr_tags)
1065 struct request_queue *q = hctx->queue;
1067 blk_mq_sub_active_requests(hctx, nr_tags);
1069 blk_mq_put_tags(hctx->tags, tag_array, nr_tags);
1070 percpu_ref_put_many(&q->q_usage_counter, nr_tags);
1073 void blk_mq_end_request_batch(struct io_comp_batch *iob)
1075 int tags[TAG_COMP_BATCH], nr_tags = 0;
1076 struct blk_mq_hw_ctx *cur_hctx = NULL;
1081 now = blk_time_get_ns();
1083 while ((rq = rq_list_pop(&iob->req_list)) != NULL) {
1085 prefetch(rq->rq_next);
1087 blk_complete_request(rq);
1089 __blk_mq_end_request_acct(rq, now);
1091 blk_mq_finish_request(rq);
1093 rq_qos_done(rq->q, rq);
1096 * If end_io handler returns NONE, then it still has
1097 * ownership of the request.
1099 if (rq->end_io && rq->end_io(rq, 0) == RQ_END_IO_NONE)
1102 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1103 if (!req_ref_put_and_test(rq))
1106 blk_crypto_free_request(rq);
1107 blk_pm_mark_last_busy(rq);
1109 if (nr_tags == TAG_COMP_BATCH || cur_hctx != rq->mq_hctx) {
1111 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1113 cur_hctx = rq->mq_hctx;
1115 tags[nr_tags++] = rq->tag;
1119 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1121 EXPORT_SYMBOL_GPL(blk_mq_end_request_batch);
1123 static void blk_complete_reqs(struct llist_head *list)
1125 struct llist_node *entry = llist_reverse_order(llist_del_all(list));
1126 struct request *rq, *next;
1128 llist_for_each_entry_safe(rq, next, entry, ipi_list)
1129 rq->q->mq_ops->complete(rq);
1132 static __latent_entropy void blk_done_softirq(struct softirq_action *h)
1134 blk_complete_reqs(this_cpu_ptr(&blk_cpu_done));
1137 static int blk_softirq_cpu_dead(unsigned int cpu)
1139 blk_complete_reqs(&per_cpu(blk_cpu_done, cpu));
1143 static void __blk_mq_complete_request_remote(void *data)
1145 __raise_softirq_irqoff(BLOCK_SOFTIRQ);
1148 static inline bool blk_mq_complete_need_ipi(struct request *rq)
1150 int cpu = raw_smp_processor_id();
1152 if (!IS_ENABLED(CONFIG_SMP) ||
1153 !test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags))
1156 * With force threaded interrupts enabled, raising softirq from an SMP
1157 * function call will always result in waking the ksoftirqd thread.
1158 * This is probably worse than completing the request on a different
1161 if (force_irqthreads())
1164 /* same CPU or cache domain and capacity? Complete locally */
1165 if (cpu == rq->mq_ctx->cpu ||
1166 (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) &&
1167 cpus_share_cache(cpu, rq->mq_ctx->cpu) &&
1168 cpus_equal_capacity(cpu, rq->mq_ctx->cpu)))
1171 /* don't try to IPI to an offline CPU */
1172 return cpu_online(rq->mq_ctx->cpu);
1175 static void blk_mq_complete_send_ipi(struct request *rq)
1179 cpu = rq->mq_ctx->cpu;
1180 if (llist_add(&rq->ipi_list, &per_cpu(blk_cpu_done, cpu)))
1181 smp_call_function_single_async(cpu, &per_cpu(blk_cpu_csd, cpu));
1184 static void blk_mq_raise_softirq(struct request *rq)
1186 struct llist_head *list;
1189 list = this_cpu_ptr(&blk_cpu_done);
1190 if (llist_add(&rq->ipi_list, list))
1191 raise_softirq(BLOCK_SOFTIRQ);
1195 bool blk_mq_complete_request_remote(struct request *rq)
1197 WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
1200 * For request which hctx has only one ctx mapping,
1201 * or a polled request, always complete locally,
1202 * it's pointless to redirect the completion.
1204 if ((rq->mq_hctx->nr_ctx == 1 &&
1205 rq->mq_ctx->cpu == raw_smp_processor_id()) ||
1206 rq->cmd_flags & REQ_POLLED)
1209 if (blk_mq_complete_need_ipi(rq)) {
1210 blk_mq_complete_send_ipi(rq);
1214 if (rq->q->nr_hw_queues == 1) {
1215 blk_mq_raise_softirq(rq);
1220 EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote);
1223 * blk_mq_complete_request - end I/O on a request
1224 * @rq: the request being processed
1227 * Complete a request by scheduling the ->complete_rq operation.
1229 void blk_mq_complete_request(struct request *rq)
1231 if (!blk_mq_complete_request_remote(rq))
1232 rq->q->mq_ops->complete(rq);
1234 EXPORT_SYMBOL(blk_mq_complete_request);
1237 * blk_mq_start_request - Start processing a request
1238 * @rq: Pointer to request to be started
1240 * Function used by device drivers to notify the block layer that a request
1241 * is going to be processed now, so blk layer can do proper initializations
1242 * such as starting the timeout timer.
1244 void blk_mq_start_request(struct request *rq)
1246 struct request_queue *q = rq->q;
1248 trace_block_rq_issue(rq);
1250 if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags) &&
1251 !blk_rq_is_passthrough(rq)) {
1252 rq->io_start_time_ns = blk_time_get_ns();
1253 rq->stats_sectors = blk_rq_sectors(rq);
1254 rq->rq_flags |= RQF_STATS;
1255 rq_qos_issue(q, rq);
1258 WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE);
1261 WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT);
1262 rq->mq_hctx->tags->rqs[rq->tag] = rq;
1264 #ifdef CONFIG_BLK_DEV_INTEGRITY
1265 if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE)
1266 q->integrity.profile->prepare_fn(rq);
1268 if (rq->bio && rq->bio->bi_opf & REQ_POLLED)
1269 WRITE_ONCE(rq->bio->bi_cookie, rq->mq_hctx->queue_num);
1271 EXPORT_SYMBOL(blk_mq_start_request);
1274 * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple
1275 * queues. This is important for md arrays to benefit from merging
1278 static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug)
1280 if (plug->multiple_queues)
1281 return BLK_MAX_REQUEST_COUNT * 2;
1282 return BLK_MAX_REQUEST_COUNT;
1285 static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq)
1287 struct request *last = rq_list_peek(&plug->mq_list);
1289 if (!plug->rq_count) {
1290 trace_block_plug(rq->q);
1291 } else if (plug->rq_count >= blk_plug_max_rq_count(plug) ||
1292 (!blk_queue_nomerges(rq->q) &&
1293 blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
1294 blk_mq_flush_plug_list(plug, false);
1296 trace_block_plug(rq->q);
1299 if (!plug->multiple_queues && last && last->q != rq->q)
1300 plug->multiple_queues = true;
1302 * Any request allocated from sched tags can't be issued to
1303 * ->queue_rqs() directly
1305 if (!plug->has_elevator && (rq->rq_flags & RQF_SCHED_TAGS))
1306 plug->has_elevator = true;
1308 rq_list_add(&plug->mq_list, rq);
1313 * blk_execute_rq_nowait - insert a request to I/O scheduler for execution
1314 * @rq: request to insert
1315 * @at_head: insert request at head or tail of queue
1318 * Insert a fully prepared request at the back of the I/O scheduler queue
1319 * for execution. Don't wait for completion.
1322 * This function will invoke @done directly if the queue is dead.
1324 void blk_execute_rq_nowait(struct request *rq, bool at_head)
1326 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1328 WARN_ON(irqs_disabled());
1329 WARN_ON(!blk_rq_is_passthrough(rq));
1331 blk_account_io_start(rq);
1334 * As plugging can be enabled for passthrough requests on a zoned
1335 * device, directly accessing the plug instead of using blk_mq_plug()
1336 * should not have any consequences.
1338 if (current->plug && !at_head) {
1339 blk_add_rq_to_plug(current->plug, rq);
1343 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1344 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING);
1346 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
1348 struct blk_rq_wait {
1349 struct completion done;
1353 static enum rq_end_io_ret blk_end_sync_rq(struct request *rq, blk_status_t ret)
1355 struct blk_rq_wait *wait = rq->end_io_data;
1358 complete(&wait->done);
1359 return RQ_END_IO_NONE;
1362 bool blk_rq_is_poll(struct request *rq)
1366 if (rq->mq_hctx->type != HCTX_TYPE_POLL)
1370 EXPORT_SYMBOL_GPL(blk_rq_is_poll);
1372 static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
1375 blk_hctx_poll(rq->q, rq->mq_hctx, NULL, 0);
1377 } while (!completion_done(wait));
1381 * blk_execute_rq - insert a request into queue for execution
1382 * @rq: request to insert
1383 * @at_head: insert request at head or tail of queue
1386 * Insert a fully prepared request at the back of the I/O scheduler queue
1387 * for execution and wait for completion.
1388 * Return: The blk_status_t result provided to blk_mq_end_request().
1390 blk_status_t blk_execute_rq(struct request *rq, bool at_head)
1392 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1393 struct blk_rq_wait wait = {
1394 .done = COMPLETION_INITIALIZER_ONSTACK(wait.done),
1397 WARN_ON(irqs_disabled());
1398 WARN_ON(!blk_rq_is_passthrough(rq));
1400 rq->end_io_data = &wait;
1401 rq->end_io = blk_end_sync_rq;
1403 blk_account_io_start(rq);
1404 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1405 blk_mq_run_hw_queue(hctx, false);
1407 if (blk_rq_is_poll(rq))
1408 blk_rq_poll_completion(rq, &wait.done);
1410 blk_wait_io(&wait.done);
1414 EXPORT_SYMBOL(blk_execute_rq);
1416 static void __blk_mq_requeue_request(struct request *rq)
1418 struct request_queue *q = rq->q;
1420 blk_mq_put_driver_tag(rq);
1422 trace_block_rq_requeue(rq);
1423 rq_qos_requeue(q, rq);
1425 if (blk_mq_request_started(rq)) {
1426 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1427 rq->rq_flags &= ~RQF_TIMED_OUT;
1431 void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
1433 struct request_queue *q = rq->q;
1434 unsigned long flags;
1436 __blk_mq_requeue_request(rq);
1438 /* this request will be re-inserted to io scheduler queue */
1439 blk_mq_sched_requeue_request(rq);
1441 spin_lock_irqsave(&q->requeue_lock, flags);
1442 list_add_tail(&rq->queuelist, &q->requeue_list);
1443 spin_unlock_irqrestore(&q->requeue_lock, flags);
1445 if (kick_requeue_list)
1446 blk_mq_kick_requeue_list(q);
1448 EXPORT_SYMBOL(blk_mq_requeue_request);
1450 static void blk_mq_requeue_work(struct work_struct *work)
1452 struct request_queue *q =
1453 container_of(work, struct request_queue, requeue_work.work);
1455 LIST_HEAD(flush_list);
1458 spin_lock_irq(&q->requeue_lock);
1459 list_splice_init(&q->requeue_list, &rq_list);
1460 list_splice_init(&q->flush_list, &flush_list);
1461 spin_unlock_irq(&q->requeue_lock);
1463 while (!list_empty(&rq_list)) {
1464 rq = list_entry(rq_list.next, struct request, queuelist);
1466 * If RQF_DONTPREP ist set, the request has been started by the
1467 * driver already and might have driver-specific data allocated
1468 * already. Insert it into the hctx dispatch list to avoid
1469 * block layer merges for the request.
1471 if (rq->rq_flags & RQF_DONTPREP) {
1472 list_del_init(&rq->queuelist);
1473 blk_mq_request_bypass_insert(rq, 0);
1475 list_del_init(&rq->queuelist);
1476 blk_mq_insert_request(rq, BLK_MQ_INSERT_AT_HEAD);
1480 while (!list_empty(&flush_list)) {
1481 rq = list_entry(flush_list.next, struct request, queuelist);
1482 list_del_init(&rq->queuelist);
1483 blk_mq_insert_request(rq, 0);
1486 blk_mq_run_hw_queues(q, false);
1489 void blk_mq_kick_requeue_list(struct request_queue *q)
1491 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0);
1493 EXPORT_SYMBOL(blk_mq_kick_requeue_list);
1495 void blk_mq_delay_kick_requeue_list(struct request_queue *q,
1496 unsigned long msecs)
1498 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work,
1499 msecs_to_jiffies(msecs));
1501 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
1503 static bool blk_is_flush_data_rq(struct request *rq)
1505 return (rq->rq_flags & RQF_FLUSH_SEQ) && !is_flush_rq(rq);
1508 static bool blk_mq_rq_inflight(struct request *rq, void *priv)
1511 * If we find a request that isn't idle we know the queue is busy
1512 * as it's checked in the iter.
1513 * Return false to stop the iteration.
1515 * In case of queue quiesce, if one flush data request is completed,
1516 * don't count it as inflight given the flush sequence is suspended,
1517 * and the original flush data request is invisible to driver, just
1518 * like other pending requests because of quiesce
1520 if (blk_mq_request_started(rq) && !(blk_queue_quiesced(rq->q) &&
1521 blk_is_flush_data_rq(rq) &&
1522 blk_mq_request_completed(rq))) {
1532 bool blk_mq_queue_inflight(struct request_queue *q)
1536 blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy);
1539 EXPORT_SYMBOL_GPL(blk_mq_queue_inflight);
1541 static void blk_mq_rq_timed_out(struct request *req)
1543 req->rq_flags |= RQF_TIMED_OUT;
1544 if (req->q->mq_ops->timeout) {
1545 enum blk_eh_timer_return ret;
1547 ret = req->q->mq_ops->timeout(req);
1548 if (ret == BLK_EH_DONE)
1550 WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER);
1556 struct blk_expired_data {
1557 bool has_timedout_rq;
1559 unsigned long timeout_start;
1562 static bool blk_mq_req_expired(struct request *rq, struct blk_expired_data *expired)
1564 unsigned long deadline;
1566 if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT)
1568 if (rq->rq_flags & RQF_TIMED_OUT)
1571 deadline = READ_ONCE(rq->deadline);
1572 if (time_after_eq(expired->timeout_start, deadline))
1575 if (expired->next == 0)
1576 expired->next = deadline;
1577 else if (time_after(expired->next, deadline))
1578 expired->next = deadline;
1582 void blk_mq_put_rq_ref(struct request *rq)
1584 if (is_flush_rq(rq)) {
1585 if (rq->end_io(rq, 0) == RQ_END_IO_FREE)
1586 blk_mq_free_request(rq);
1587 } else if (req_ref_put_and_test(rq)) {
1588 __blk_mq_free_request(rq);
1592 static bool blk_mq_check_expired(struct request *rq, void *priv)
1594 struct blk_expired_data *expired = priv;
1597 * blk_mq_queue_tag_busy_iter() has locked the request, so it cannot
1598 * be reallocated underneath the timeout handler's processing, then
1599 * the expire check is reliable. If the request is not expired, then
1600 * it was completed and reallocated as a new request after returning
1601 * from blk_mq_check_expired().
1603 if (blk_mq_req_expired(rq, expired)) {
1604 expired->has_timedout_rq = true;
1610 static bool blk_mq_handle_expired(struct request *rq, void *priv)
1612 struct blk_expired_data *expired = priv;
1614 if (blk_mq_req_expired(rq, expired))
1615 blk_mq_rq_timed_out(rq);
1619 static void blk_mq_timeout_work(struct work_struct *work)
1621 struct request_queue *q =
1622 container_of(work, struct request_queue, timeout_work);
1623 struct blk_expired_data expired = {
1624 .timeout_start = jiffies,
1626 struct blk_mq_hw_ctx *hctx;
1629 /* A deadlock might occur if a request is stuck requiring a
1630 * timeout at the same time a queue freeze is waiting
1631 * completion, since the timeout code would not be able to
1632 * acquire the queue reference here.
1634 * That's why we don't use blk_queue_enter here; instead, we use
1635 * percpu_ref_tryget directly, because we need to be able to
1636 * obtain a reference even in the short window between the queue
1637 * starting to freeze, by dropping the first reference in
1638 * blk_freeze_queue_start, and the moment the last request is
1639 * consumed, marked by the instant q_usage_counter reaches
1642 if (!percpu_ref_tryget(&q->q_usage_counter))
1645 /* check if there is any timed-out request */
1646 blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &expired);
1647 if (expired.has_timedout_rq) {
1649 * Before walking tags, we must ensure any submit started
1650 * before the current time has finished. Since the submit
1651 * uses srcu or rcu, wait for a synchronization point to
1652 * ensure all running submits have finished
1654 blk_mq_wait_quiesce_done(q->tag_set);
1657 blk_mq_queue_tag_busy_iter(q, blk_mq_handle_expired, &expired);
1660 if (expired.next != 0) {
1661 mod_timer(&q->timeout, expired.next);
1664 * Request timeouts are handled as a forward rolling timer. If
1665 * we end up here it means that no requests are pending and
1666 * also that no request has been pending for a while. Mark
1667 * each hctx as idle.
1669 queue_for_each_hw_ctx(q, hctx, i) {
1670 /* the hctx may be unmapped, so check it here */
1671 if (blk_mq_hw_queue_mapped(hctx))
1672 blk_mq_tag_idle(hctx);
1678 struct flush_busy_ctx_data {
1679 struct blk_mq_hw_ctx *hctx;
1680 struct list_head *list;
1683 static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
1685 struct flush_busy_ctx_data *flush_data = data;
1686 struct blk_mq_hw_ctx *hctx = flush_data->hctx;
1687 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1688 enum hctx_type type = hctx->type;
1690 spin_lock(&ctx->lock);
1691 list_splice_tail_init(&ctx->rq_lists[type], flush_data->list);
1692 sbitmap_clear_bit(sb, bitnr);
1693 spin_unlock(&ctx->lock);
1698 * Process software queues that have been marked busy, splicing them
1699 * to the for-dispatch
1701 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
1703 struct flush_busy_ctx_data data = {
1708 sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
1710 EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs);
1712 struct dispatch_rq_data {
1713 struct blk_mq_hw_ctx *hctx;
1717 static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr,
1720 struct dispatch_rq_data *dispatch_data = data;
1721 struct blk_mq_hw_ctx *hctx = dispatch_data->hctx;
1722 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1723 enum hctx_type type = hctx->type;
1725 spin_lock(&ctx->lock);
1726 if (!list_empty(&ctx->rq_lists[type])) {
1727 dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next);
1728 list_del_init(&dispatch_data->rq->queuelist);
1729 if (list_empty(&ctx->rq_lists[type]))
1730 sbitmap_clear_bit(sb, bitnr);
1732 spin_unlock(&ctx->lock);
1734 return !dispatch_data->rq;
1737 struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
1738 struct blk_mq_ctx *start)
1740 unsigned off = start ? start->index_hw[hctx->type] : 0;
1741 struct dispatch_rq_data data = {
1746 __sbitmap_for_each_set(&hctx->ctx_map, off,
1747 dispatch_rq_from_ctx, &data);
1752 bool __blk_mq_alloc_driver_tag(struct request *rq)
1754 struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags;
1755 unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags;
1758 blk_mq_tag_busy(rq->mq_hctx);
1760 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) {
1761 bt = &rq->mq_hctx->tags->breserved_tags;
1764 if (!hctx_may_queue(rq->mq_hctx, bt))
1768 tag = __sbitmap_queue_get(bt);
1769 if (tag == BLK_MQ_NO_TAG)
1772 rq->tag = tag + tag_offset;
1773 blk_mq_inc_active_requests(rq->mq_hctx);
1777 static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
1778 int flags, void *key)
1780 struct blk_mq_hw_ctx *hctx;
1782 hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
1784 spin_lock(&hctx->dispatch_wait_lock);
1785 if (!list_empty(&wait->entry)) {
1786 struct sbitmap_queue *sbq;
1788 list_del_init(&wait->entry);
1789 sbq = &hctx->tags->bitmap_tags;
1790 atomic_dec(&sbq->ws_active);
1792 spin_unlock(&hctx->dispatch_wait_lock);
1794 blk_mq_run_hw_queue(hctx, true);
1799 * Mark us waiting for a tag. For shared tags, this involves hooking us into
1800 * the tag wakeups. For non-shared tags, we can simply mark us needing a
1801 * restart. For both cases, take care to check the condition again after
1802 * marking us as waiting.
1804 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
1807 struct sbitmap_queue *sbq;
1808 struct wait_queue_head *wq;
1809 wait_queue_entry_t *wait;
1812 if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
1813 !(blk_mq_is_shared_tags(hctx->flags))) {
1814 blk_mq_sched_mark_restart_hctx(hctx);
1817 * It's possible that a tag was freed in the window between the
1818 * allocation failure and adding the hardware queue to the wait
1821 * Don't clear RESTART here, someone else could have set it.
1822 * At most this will cost an extra queue run.
1824 return blk_mq_get_driver_tag(rq);
1827 wait = &hctx->dispatch_wait;
1828 if (!list_empty_careful(&wait->entry))
1831 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag))
1832 sbq = &hctx->tags->breserved_tags;
1834 sbq = &hctx->tags->bitmap_tags;
1835 wq = &bt_wait_ptr(sbq, hctx)->wait;
1837 spin_lock_irq(&wq->lock);
1838 spin_lock(&hctx->dispatch_wait_lock);
1839 if (!list_empty(&wait->entry)) {
1840 spin_unlock(&hctx->dispatch_wait_lock);
1841 spin_unlock_irq(&wq->lock);
1845 atomic_inc(&sbq->ws_active);
1846 wait->flags &= ~WQ_FLAG_EXCLUSIVE;
1847 __add_wait_queue(wq, wait);
1850 * Add one explicit barrier since blk_mq_get_driver_tag() may
1851 * not imply barrier in case of failure.
1853 * Order adding us to wait queue and allocating driver tag.
1855 * The pair is the one implied in sbitmap_queue_wake_up() which
1856 * orders clearing sbitmap tag bits and waitqueue_active() in
1857 * __sbitmap_queue_wake_up(), since waitqueue_active() is lockless
1859 * Otherwise, re-order of adding wait queue and getting driver tag
1860 * may cause __sbitmap_queue_wake_up() to wake up nothing because
1861 * the waitqueue_active() may not observe us in wait queue.
1866 * It's possible that a tag was freed in the window between the
1867 * allocation failure and adding the hardware queue to the wait
1870 ret = blk_mq_get_driver_tag(rq);
1872 spin_unlock(&hctx->dispatch_wait_lock);
1873 spin_unlock_irq(&wq->lock);
1878 * We got a tag, remove ourselves from the wait queue to ensure
1879 * someone else gets the wakeup.
1881 list_del_init(&wait->entry);
1882 atomic_dec(&sbq->ws_active);
1883 spin_unlock(&hctx->dispatch_wait_lock);
1884 spin_unlock_irq(&wq->lock);
1889 #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
1890 #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
1892 * Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
1893 * - EWMA is one simple way to compute running average value
1894 * - weight(7/8 and 1/8) is applied so that it can decrease exponentially
1895 * - take 4 as factor for avoiding to get too small(0) result, and this
1896 * factor doesn't matter because EWMA decreases exponentially
1898 static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy)
1902 ewma = hctx->dispatch_busy;
1907 ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1;
1909 ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR;
1910 ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT;
1912 hctx->dispatch_busy = ewma;
1915 #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
1917 static void blk_mq_handle_dev_resource(struct request *rq,
1918 struct list_head *list)
1920 list_add(&rq->queuelist, list);
1921 __blk_mq_requeue_request(rq);
1924 static void blk_mq_handle_zone_resource(struct request *rq,
1925 struct list_head *zone_list)
1928 * If we end up here it is because we cannot dispatch a request to a
1929 * specific zone due to LLD level zone-write locking or other zone
1930 * related resource not being available. In this case, set the request
1931 * aside in zone_list for retrying it later.
1933 list_add(&rq->queuelist, zone_list);
1934 __blk_mq_requeue_request(rq);
1937 enum prep_dispatch {
1939 PREP_DISPATCH_NO_TAG,
1940 PREP_DISPATCH_NO_BUDGET,
1943 static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
1946 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1947 int budget_token = -1;
1950 budget_token = blk_mq_get_dispatch_budget(rq->q);
1951 if (budget_token < 0) {
1952 blk_mq_put_driver_tag(rq);
1953 return PREP_DISPATCH_NO_BUDGET;
1955 blk_mq_set_rq_budget_token(rq, budget_token);
1958 if (!blk_mq_get_driver_tag(rq)) {
1960 * The initial allocation attempt failed, so we need to
1961 * rerun the hardware queue when a tag is freed. The
1962 * waitqueue takes care of that. If the queue is run
1963 * before we add this entry back on the dispatch list,
1964 * we'll re-run it below.
1966 if (!blk_mq_mark_tag_wait(hctx, rq)) {
1968 * All budgets not got from this function will be put
1969 * together during handling partial dispatch
1972 blk_mq_put_dispatch_budget(rq->q, budget_token);
1973 return PREP_DISPATCH_NO_TAG;
1977 return PREP_DISPATCH_OK;
1980 /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
1981 static void blk_mq_release_budgets(struct request_queue *q,
1982 struct list_head *list)
1986 list_for_each_entry(rq, list, queuelist) {
1987 int budget_token = blk_mq_get_rq_budget_token(rq);
1989 if (budget_token >= 0)
1990 blk_mq_put_dispatch_budget(q, budget_token);
1995 * blk_mq_commit_rqs will notify driver using bd->last that there is no
1996 * more requests. (See comment in struct blk_mq_ops for commit_rqs for
1998 * Attention, we should explicitly call this in unusual cases:
1999 * 1) did not queue everything initially scheduled to queue
2000 * 2) the last attempt to queue a request failed
2002 static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int queued,
2005 if (hctx->queue->mq_ops->commit_rqs && queued) {
2006 trace_block_unplug(hctx->queue, queued, !from_schedule);
2007 hctx->queue->mq_ops->commit_rqs(hctx);
2012 * Returns true if we did some work AND can potentially do more.
2014 bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
2015 unsigned int nr_budgets)
2017 enum prep_dispatch prep;
2018 struct request_queue *q = hctx->queue;
2021 blk_status_t ret = BLK_STS_OK;
2022 LIST_HEAD(zone_list);
2023 bool needs_resource = false;
2025 if (list_empty(list))
2029 * Now process all the entries, sending them to the driver.
2033 struct blk_mq_queue_data bd;
2035 rq = list_first_entry(list, struct request, queuelist);
2037 WARN_ON_ONCE(hctx != rq->mq_hctx);
2038 prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets);
2039 if (prep != PREP_DISPATCH_OK)
2042 list_del_init(&rq->queuelist);
2045 bd.last = list_empty(list);
2048 * once the request is queued to lld, no need to cover the
2053 ret = q->mq_ops->queue_rq(hctx, &bd);
2058 case BLK_STS_RESOURCE:
2059 needs_resource = true;
2061 case BLK_STS_DEV_RESOURCE:
2062 blk_mq_handle_dev_resource(rq, list);
2064 case BLK_STS_ZONE_RESOURCE:
2066 * Move the request to zone_list and keep going through
2067 * the dispatch list to find more requests the drive can
2070 blk_mq_handle_zone_resource(rq, &zone_list);
2071 needs_resource = true;
2074 blk_mq_end_request(rq, ret);
2076 } while (!list_empty(list));
2078 if (!list_empty(&zone_list))
2079 list_splice_tail_init(&zone_list, list);
2081 /* If we didn't flush the entire list, we could have told the driver
2082 * there was more coming, but that turned out to be a lie.
2084 if (!list_empty(list) || ret != BLK_STS_OK)
2085 blk_mq_commit_rqs(hctx, queued, false);
2088 * Any items that need requeuing? Stuff them into hctx->dispatch,
2089 * that is where we will continue on next queue run.
2091 if (!list_empty(list)) {
2093 /* For non-shared tags, the RESTART check will suffice */
2094 bool no_tag = prep == PREP_DISPATCH_NO_TAG &&
2095 ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) ||
2096 blk_mq_is_shared_tags(hctx->flags));
2099 blk_mq_release_budgets(q, list);
2101 spin_lock(&hctx->lock);
2102 list_splice_tail_init(list, &hctx->dispatch);
2103 spin_unlock(&hctx->lock);
2106 * Order adding requests to hctx->dispatch and checking
2107 * SCHED_RESTART flag. The pair of this smp_mb() is the one
2108 * in blk_mq_sched_restart(). Avoid restart code path to
2109 * miss the new added requests to hctx->dispatch, meantime
2110 * SCHED_RESTART is observed here.
2115 * If SCHED_RESTART was set by the caller of this function and
2116 * it is no longer set that means that it was cleared by another
2117 * thread and hence that a queue rerun is needed.
2119 * If 'no_tag' is set, that means that we failed getting
2120 * a driver tag with an I/O scheduler attached. If our dispatch
2121 * waitqueue is no longer active, ensure that we run the queue
2122 * AFTER adding our entries back to the list.
2124 * If no I/O scheduler has been configured it is possible that
2125 * the hardware queue got stopped and restarted before requests
2126 * were pushed back onto the dispatch list. Rerun the queue to
2127 * avoid starvation. Notes:
2128 * - blk_mq_run_hw_queue() checks whether or not a queue has
2129 * been stopped before rerunning a queue.
2130 * - Some but not all block drivers stop a queue before
2131 * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
2134 * If driver returns BLK_STS_RESOURCE and SCHED_RESTART
2135 * bit is set, run queue after a delay to avoid IO stalls
2136 * that could otherwise occur if the queue is idle. We'll do
2137 * similar if we couldn't get budget or couldn't lock a zone
2138 * and SCHED_RESTART is set.
2140 needs_restart = blk_mq_sched_needs_restart(hctx);
2141 if (prep == PREP_DISPATCH_NO_BUDGET)
2142 needs_resource = true;
2143 if (!needs_restart ||
2144 (no_tag && list_empty_careful(&hctx->dispatch_wait.entry)))
2145 blk_mq_run_hw_queue(hctx, true);
2146 else if (needs_resource)
2147 blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
2149 blk_mq_update_dispatch_busy(hctx, true);
2153 blk_mq_update_dispatch_busy(hctx, false);
2157 static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx)
2159 int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask);
2161 if (cpu >= nr_cpu_ids)
2162 cpu = cpumask_first(hctx->cpumask);
2167 * It'd be great if the workqueue API had a way to pass
2168 * in a mask and had some smarts for more clever placement.
2169 * For now we just round-robin here, switching for every
2170 * BLK_MQ_CPU_WORK_BATCH queued items.
2172 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
2175 int next_cpu = hctx->next_cpu;
2177 if (hctx->queue->nr_hw_queues == 1)
2178 return WORK_CPU_UNBOUND;
2180 if (--hctx->next_cpu_batch <= 0) {
2182 next_cpu = cpumask_next_and(next_cpu, hctx->cpumask,
2184 if (next_cpu >= nr_cpu_ids)
2185 next_cpu = blk_mq_first_mapped_cpu(hctx);
2186 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
2190 * Do unbound schedule if we can't find a online CPU for this hctx,
2191 * and it should only happen in the path of handling CPU DEAD.
2193 if (!cpu_online(next_cpu)) {
2200 * Make sure to re-select CPU next time once after CPUs
2201 * in hctx->cpumask become online again.
2203 hctx->next_cpu = next_cpu;
2204 hctx->next_cpu_batch = 1;
2205 return WORK_CPU_UNBOUND;
2208 hctx->next_cpu = next_cpu;
2213 * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
2214 * @hctx: Pointer to the hardware queue to run.
2215 * @msecs: Milliseconds of delay to wait before running the queue.
2217 * Run a hardware queue asynchronously with a delay of @msecs.
2219 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
2221 if (unlikely(blk_mq_hctx_stopped(hctx)))
2223 kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
2224 msecs_to_jiffies(msecs));
2226 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue);
2229 * blk_mq_run_hw_queue - Start to run a hardware queue.
2230 * @hctx: Pointer to the hardware queue to run.
2231 * @async: If we want to run the queue asynchronously.
2233 * Check if the request queue is not in a quiesced state and if there are
2234 * pending requests to be sent. If this is true, run the queue to send requests
2237 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2242 * We can't run the queue inline with interrupts disabled.
2244 WARN_ON_ONCE(!async && in_interrupt());
2246 might_sleep_if(!async && hctx->flags & BLK_MQ_F_BLOCKING);
2249 * When queue is quiesced, we may be switching io scheduler, or
2250 * updating nr_hw_queues, or other things, and we can't run queue
2251 * any more, even __blk_mq_hctx_has_pending() can't be called safely.
2253 * And queue will be rerun in blk_mq_unquiesce_queue() if it is
2256 __blk_mq_run_dispatch_ops(hctx->queue, false,
2257 need_run = !blk_queue_quiesced(hctx->queue) &&
2258 blk_mq_hctx_has_pending(hctx));
2263 if (async || !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) {
2264 blk_mq_delay_run_hw_queue(hctx, 0);
2268 blk_mq_run_dispatch_ops(hctx->queue,
2269 blk_mq_sched_dispatch_requests(hctx));
2271 EXPORT_SYMBOL(blk_mq_run_hw_queue);
2274 * Return prefered queue to dispatch from (if any) for non-mq aware IO
2277 static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
2279 struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
2281 * If the IO scheduler does not respect hardware queues when
2282 * dispatching, we just don't bother with multiple HW queues and
2283 * dispatch from hctx for the current CPU since running multiple queues
2284 * just causes lock contention inside the scheduler and pointless cache
2287 struct blk_mq_hw_ctx *hctx = ctx->hctxs[HCTX_TYPE_DEFAULT];
2289 if (!blk_mq_hctx_stopped(hctx))
2295 * blk_mq_run_hw_queues - Run all hardware queues in a request queue.
2296 * @q: Pointer to the request queue to run.
2297 * @async: If we want to run the queue asynchronously.
2299 void blk_mq_run_hw_queues(struct request_queue *q, bool async)
2301 struct blk_mq_hw_ctx *hctx, *sq_hctx;
2305 if (blk_queue_sq_sched(q))
2306 sq_hctx = blk_mq_get_sq_hctx(q);
2307 queue_for_each_hw_ctx(q, hctx, i) {
2308 if (blk_mq_hctx_stopped(hctx))
2311 * Dispatch from this hctx either if there's no hctx preferred
2312 * by IO scheduler or if it has requests that bypass the
2315 if (!sq_hctx || sq_hctx == hctx ||
2316 !list_empty_careful(&hctx->dispatch))
2317 blk_mq_run_hw_queue(hctx, async);
2320 EXPORT_SYMBOL(blk_mq_run_hw_queues);
2323 * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
2324 * @q: Pointer to the request queue to run.
2325 * @msecs: Milliseconds of delay to wait before running the queues.
2327 void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs)
2329 struct blk_mq_hw_ctx *hctx, *sq_hctx;
2333 if (blk_queue_sq_sched(q))
2334 sq_hctx = blk_mq_get_sq_hctx(q);
2335 queue_for_each_hw_ctx(q, hctx, i) {
2336 if (blk_mq_hctx_stopped(hctx))
2339 * If there is already a run_work pending, leave the
2340 * pending delay untouched. Otherwise, a hctx can stall
2341 * if another hctx is re-delaying the other's work
2342 * before the work executes.
2344 if (delayed_work_pending(&hctx->run_work))
2347 * Dispatch from this hctx either if there's no hctx preferred
2348 * by IO scheduler or if it has requests that bypass the
2351 if (!sq_hctx || sq_hctx == hctx ||
2352 !list_empty_careful(&hctx->dispatch))
2353 blk_mq_delay_run_hw_queue(hctx, msecs);
2356 EXPORT_SYMBOL(blk_mq_delay_run_hw_queues);
2359 * This function is often used for pausing .queue_rq() by driver when
2360 * there isn't enough resource or some conditions aren't satisfied, and
2361 * BLK_STS_RESOURCE is usually returned.
2363 * We do not guarantee that dispatch can be drained or blocked
2364 * after blk_mq_stop_hw_queue() returns. Please use
2365 * blk_mq_quiesce_queue() for that requirement.
2367 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
2369 cancel_delayed_work(&hctx->run_work);
2371 set_bit(BLK_MQ_S_STOPPED, &hctx->state);
2373 EXPORT_SYMBOL(blk_mq_stop_hw_queue);
2376 * This function is often used for pausing .queue_rq() by driver when
2377 * there isn't enough resource or some conditions aren't satisfied, and
2378 * BLK_STS_RESOURCE is usually returned.
2380 * We do not guarantee that dispatch can be drained or blocked
2381 * after blk_mq_stop_hw_queues() returns. Please use
2382 * blk_mq_quiesce_queue() for that requirement.
2384 void blk_mq_stop_hw_queues(struct request_queue *q)
2386 struct blk_mq_hw_ctx *hctx;
2389 queue_for_each_hw_ctx(q, hctx, i)
2390 blk_mq_stop_hw_queue(hctx);
2392 EXPORT_SYMBOL(blk_mq_stop_hw_queues);
2394 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
2396 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2398 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING);
2400 EXPORT_SYMBOL(blk_mq_start_hw_queue);
2402 void blk_mq_start_hw_queues(struct request_queue *q)
2404 struct blk_mq_hw_ctx *hctx;
2407 queue_for_each_hw_ctx(q, hctx, i)
2408 blk_mq_start_hw_queue(hctx);
2410 EXPORT_SYMBOL(blk_mq_start_hw_queues);
2412 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2414 if (!blk_mq_hctx_stopped(hctx))
2417 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2418 blk_mq_run_hw_queue(hctx, async);
2420 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue);
2422 void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
2424 struct blk_mq_hw_ctx *hctx;
2427 queue_for_each_hw_ctx(q, hctx, i)
2428 blk_mq_start_stopped_hw_queue(hctx, async ||
2429 (hctx->flags & BLK_MQ_F_BLOCKING));
2431 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
2433 static void blk_mq_run_work_fn(struct work_struct *work)
2435 struct blk_mq_hw_ctx *hctx =
2436 container_of(work, struct blk_mq_hw_ctx, run_work.work);
2438 blk_mq_run_dispatch_ops(hctx->queue,
2439 blk_mq_sched_dispatch_requests(hctx));
2443 * blk_mq_request_bypass_insert - Insert a request at dispatch list.
2444 * @rq: Pointer to request to be inserted.
2445 * @flags: BLK_MQ_INSERT_*
2447 * Should only be used carefully, when the caller knows we want to
2448 * bypass a potential IO scheduler on the target device.
2450 static void blk_mq_request_bypass_insert(struct request *rq, blk_insert_t flags)
2452 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2454 spin_lock(&hctx->lock);
2455 if (flags & BLK_MQ_INSERT_AT_HEAD)
2456 list_add(&rq->queuelist, &hctx->dispatch);
2458 list_add_tail(&rq->queuelist, &hctx->dispatch);
2459 spin_unlock(&hctx->lock);
2462 static void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx,
2463 struct blk_mq_ctx *ctx, struct list_head *list,
2464 bool run_queue_async)
2467 enum hctx_type type = hctx->type;
2470 * Try to issue requests directly if the hw queue isn't busy to save an
2471 * extra enqueue & dequeue to the sw queue.
2473 if (!hctx->dispatch_busy && !run_queue_async) {
2474 blk_mq_run_dispatch_ops(hctx->queue,
2475 blk_mq_try_issue_list_directly(hctx, list));
2476 if (list_empty(list))
2481 * preemption doesn't flush plug list, so it's possible ctx->cpu is
2484 list_for_each_entry(rq, list, queuelist) {
2485 BUG_ON(rq->mq_ctx != ctx);
2486 trace_block_rq_insert(rq);
2487 if (rq->cmd_flags & REQ_NOWAIT)
2488 run_queue_async = true;
2491 spin_lock(&ctx->lock);
2492 list_splice_tail_init(list, &ctx->rq_lists[type]);
2493 blk_mq_hctx_mark_pending(hctx, ctx);
2494 spin_unlock(&ctx->lock);
2496 blk_mq_run_hw_queue(hctx, run_queue_async);
2499 static void blk_mq_insert_request(struct request *rq, blk_insert_t flags)
2501 struct request_queue *q = rq->q;
2502 struct blk_mq_ctx *ctx = rq->mq_ctx;
2503 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2505 if (blk_rq_is_passthrough(rq)) {
2507 * Passthrough request have to be added to hctx->dispatch
2508 * directly. The device may be in a situation where it can't
2509 * handle FS request, and always returns BLK_STS_RESOURCE for
2510 * them, which gets them added to hctx->dispatch.
2512 * If a passthrough request is required to unblock the queues,
2513 * and it is added to the scheduler queue, there is no chance to
2514 * dispatch it given we prioritize requests in hctx->dispatch.
2516 blk_mq_request_bypass_insert(rq, flags);
2517 } else if (req_op(rq) == REQ_OP_FLUSH) {
2519 * Firstly normal IO request is inserted to scheduler queue or
2520 * sw queue, meantime we add flush request to dispatch queue(
2521 * hctx->dispatch) directly and there is at most one in-flight
2522 * flush request for each hw queue, so it doesn't matter to add
2523 * flush request to tail or front of the dispatch queue.
2525 * Secondly in case of NCQ, flush request belongs to non-NCQ
2526 * command, and queueing it will fail when there is any
2527 * in-flight normal IO request(NCQ command). When adding flush
2528 * rq to the front of hctx->dispatch, it is easier to introduce
2529 * extra time to flush rq's latency because of S_SCHED_RESTART
2530 * compared with adding to the tail of dispatch queue, then
2531 * chance of flush merge is increased, and less flush requests
2532 * will be issued to controller. It is observed that ~10% time
2533 * is saved in blktests block/004 on disk attached to AHCI/NCQ
2534 * drive when adding flush rq to the front of hctx->dispatch.
2536 * Simply queue flush rq to the front of hctx->dispatch so that
2537 * intensive flush workloads can benefit in case of NCQ HW.
2539 blk_mq_request_bypass_insert(rq, BLK_MQ_INSERT_AT_HEAD);
2540 } else if (q->elevator) {
2543 WARN_ON_ONCE(rq->tag != BLK_MQ_NO_TAG);
2545 list_add(&rq->queuelist, &list);
2546 q->elevator->type->ops.insert_requests(hctx, &list, flags);
2548 trace_block_rq_insert(rq);
2550 spin_lock(&ctx->lock);
2551 if (flags & BLK_MQ_INSERT_AT_HEAD)
2552 list_add(&rq->queuelist, &ctx->rq_lists[hctx->type]);
2554 list_add_tail(&rq->queuelist,
2555 &ctx->rq_lists[hctx->type]);
2556 blk_mq_hctx_mark_pending(hctx, ctx);
2557 spin_unlock(&ctx->lock);
2561 static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
2562 unsigned int nr_segs)
2566 if (bio->bi_opf & REQ_RAHEAD)
2567 rq->cmd_flags |= REQ_FAILFAST_MASK;
2569 rq->__sector = bio->bi_iter.bi_sector;
2570 rq->write_hint = bio->bi_write_hint;
2571 blk_rq_bio_prep(rq, bio, nr_segs);
2573 /* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */
2574 err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO);
2577 blk_account_io_start(rq);
2580 static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
2581 struct request *rq, bool last)
2583 struct request_queue *q = rq->q;
2584 struct blk_mq_queue_data bd = {
2591 * For OK queue, we are done. For error, caller may kill it.
2592 * Any other error (busy), just add it to our list as we
2593 * previously would have done.
2595 ret = q->mq_ops->queue_rq(hctx, &bd);
2598 blk_mq_update_dispatch_busy(hctx, false);
2600 case BLK_STS_RESOURCE:
2601 case BLK_STS_DEV_RESOURCE:
2602 blk_mq_update_dispatch_busy(hctx, true);
2603 __blk_mq_requeue_request(rq);
2606 blk_mq_update_dispatch_busy(hctx, false);
2613 static bool blk_mq_get_budget_and_tag(struct request *rq)
2617 budget_token = blk_mq_get_dispatch_budget(rq->q);
2618 if (budget_token < 0)
2620 blk_mq_set_rq_budget_token(rq, budget_token);
2621 if (!blk_mq_get_driver_tag(rq)) {
2622 blk_mq_put_dispatch_budget(rq->q, budget_token);
2629 * blk_mq_try_issue_directly - Try to send a request directly to device driver.
2630 * @hctx: Pointer of the associated hardware queue.
2631 * @rq: Pointer to request to be sent.
2633 * If the device has enough resources to accept a new request now, send the
2634 * request directly to device driver. Else, insert at hctx->dispatch queue, so
2635 * we can try send it another time in the future. Requests inserted at this
2636 * queue have higher priority.
2638 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
2643 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2644 blk_mq_insert_request(rq, 0);
2648 if ((rq->rq_flags & RQF_USE_SCHED) || !blk_mq_get_budget_and_tag(rq)) {
2649 blk_mq_insert_request(rq, 0);
2650 blk_mq_run_hw_queue(hctx, rq->cmd_flags & REQ_NOWAIT);
2654 ret = __blk_mq_issue_directly(hctx, rq, true);
2658 case BLK_STS_RESOURCE:
2659 case BLK_STS_DEV_RESOURCE:
2660 blk_mq_request_bypass_insert(rq, 0);
2661 blk_mq_run_hw_queue(hctx, false);
2664 blk_mq_end_request(rq, ret);
2669 static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
2671 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2673 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2674 blk_mq_insert_request(rq, 0);
2678 if (!blk_mq_get_budget_and_tag(rq))
2679 return BLK_STS_RESOURCE;
2680 return __blk_mq_issue_directly(hctx, rq, last);
2683 static void blk_mq_plug_issue_direct(struct blk_plug *plug)
2685 struct blk_mq_hw_ctx *hctx = NULL;
2688 blk_status_t ret = BLK_STS_OK;
2690 while ((rq = rq_list_pop(&plug->mq_list))) {
2691 bool last = rq_list_empty(plug->mq_list);
2693 if (hctx != rq->mq_hctx) {
2695 blk_mq_commit_rqs(hctx, queued, false);
2701 ret = blk_mq_request_issue_directly(rq, last);
2706 case BLK_STS_RESOURCE:
2707 case BLK_STS_DEV_RESOURCE:
2708 blk_mq_request_bypass_insert(rq, 0);
2709 blk_mq_run_hw_queue(hctx, false);
2712 blk_mq_end_request(rq, ret);
2718 if (ret != BLK_STS_OK)
2719 blk_mq_commit_rqs(hctx, queued, false);
2722 static void __blk_mq_flush_plug_list(struct request_queue *q,
2723 struct blk_plug *plug)
2725 if (blk_queue_quiesced(q))
2727 q->mq_ops->queue_rqs(&plug->mq_list);
2730 static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
2732 struct blk_mq_hw_ctx *this_hctx = NULL;
2733 struct blk_mq_ctx *this_ctx = NULL;
2734 struct request *requeue_list = NULL;
2735 struct request **requeue_lastp = &requeue_list;
2736 unsigned int depth = 0;
2737 bool is_passthrough = false;
2741 struct request *rq = rq_list_pop(&plug->mq_list);
2744 this_hctx = rq->mq_hctx;
2745 this_ctx = rq->mq_ctx;
2746 is_passthrough = blk_rq_is_passthrough(rq);
2747 } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx ||
2748 is_passthrough != blk_rq_is_passthrough(rq)) {
2749 rq_list_add_tail(&requeue_lastp, rq);
2752 list_add(&rq->queuelist, &list);
2754 } while (!rq_list_empty(plug->mq_list));
2756 plug->mq_list = requeue_list;
2757 trace_block_unplug(this_hctx->queue, depth, !from_sched);
2759 percpu_ref_get(&this_hctx->queue->q_usage_counter);
2760 /* passthrough requests should never be issued to the I/O scheduler */
2761 if (is_passthrough) {
2762 spin_lock(&this_hctx->lock);
2763 list_splice_tail_init(&list, &this_hctx->dispatch);
2764 spin_unlock(&this_hctx->lock);
2765 blk_mq_run_hw_queue(this_hctx, from_sched);
2766 } else if (this_hctx->queue->elevator) {
2767 this_hctx->queue->elevator->type->ops.insert_requests(this_hctx,
2769 blk_mq_run_hw_queue(this_hctx, from_sched);
2771 blk_mq_insert_requests(this_hctx, this_ctx, &list, from_sched);
2773 percpu_ref_put(&this_hctx->queue->q_usage_counter);
2776 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
2781 * We may have been called recursively midway through handling
2782 * plug->mq_list via a schedule() in the driver's queue_rq() callback.
2783 * To avoid mq_list changing under our feet, clear rq_count early and
2784 * bail out specifically if rq_count is 0 rather than checking
2785 * whether the mq_list is empty.
2787 if (plug->rq_count == 0)
2791 if (!plug->multiple_queues && !plug->has_elevator && !from_schedule) {
2792 struct request_queue *q;
2794 rq = rq_list_peek(&plug->mq_list);
2798 * Peek first request and see if we have a ->queue_rqs() hook.
2799 * If we do, we can dispatch the whole plug list in one go. We
2800 * already know at this point that all requests belong to the
2801 * same queue, caller must ensure that's the case.
2803 if (q->mq_ops->queue_rqs) {
2804 blk_mq_run_dispatch_ops(q,
2805 __blk_mq_flush_plug_list(q, plug));
2806 if (rq_list_empty(plug->mq_list))
2810 blk_mq_run_dispatch_ops(q,
2811 blk_mq_plug_issue_direct(plug));
2812 if (rq_list_empty(plug->mq_list))
2817 blk_mq_dispatch_plug_list(plug, from_schedule);
2818 } while (!rq_list_empty(plug->mq_list));
2821 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
2822 struct list_head *list)
2825 blk_status_t ret = BLK_STS_OK;
2827 while (!list_empty(list)) {
2828 struct request *rq = list_first_entry(list, struct request,
2831 list_del_init(&rq->queuelist);
2832 ret = blk_mq_request_issue_directly(rq, list_empty(list));
2837 case BLK_STS_RESOURCE:
2838 case BLK_STS_DEV_RESOURCE:
2839 blk_mq_request_bypass_insert(rq, 0);
2840 if (list_empty(list))
2841 blk_mq_run_hw_queue(hctx, false);
2844 blk_mq_end_request(rq, ret);
2850 if (ret != BLK_STS_OK)
2851 blk_mq_commit_rqs(hctx, queued, false);
2854 static bool blk_mq_attempt_bio_merge(struct request_queue *q,
2855 struct bio *bio, unsigned int nr_segs)
2857 if (!blk_queue_nomerges(q) && bio_mergeable(bio)) {
2858 if (blk_attempt_plug_merge(q, bio, nr_segs))
2860 if (blk_mq_sched_bio_merge(q, bio, nr_segs))
2866 static struct request *blk_mq_get_new_requests(struct request_queue *q,
2867 struct blk_plug *plug,
2871 struct blk_mq_alloc_data data = {
2874 .cmd_flags = bio->bi_opf,
2878 rq_qos_throttle(q, bio);
2881 data.nr_tags = plug->nr_ios;
2883 data.cached_rq = &plug->cached_rq;
2886 rq = __blk_mq_alloc_requests(&data);
2889 rq_qos_cleanup(q, bio);
2890 if (bio->bi_opf & REQ_NOWAIT)
2891 bio_wouldblock_error(bio);
2896 * Check if there is a suitable cached request and return it.
2898 static struct request *blk_mq_peek_cached_request(struct blk_plug *plug,
2899 struct request_queue *q, blk_opf_t opf)
2901 enum hctx_type type = blk_mq_get_hctx_type(opf);
2906 rq = rq_list_peek(&plug->cached_rq);
2907 if (!rq || rq->q != q)
2909 if (type != rq->mq_hctx->type &&
2910 (type != HCTX_TYPE_READ || rq->mq_hctx->type != HCTX_TYPE_DEFAULT))
2912 if (op_is_flush(rq->cmd_flags) != op_is_flush(opf))
2917 static void blk_mq_use_cached_rq(struct request *rq, struct blk_plug *plug,
2920 WARN_ON_ONCE(rq_list_peek(&plug->cached_rq) != rq);
2923 * If any qos ->throttle() end up blocking, we will have flushed the
2924 * plug and hence killed the cached_rq list as well. Pop this entry
2925 * before we throttle.
2927 plug->cached_rq = rq_list_next(rq);
2928 rq_qos_throttle(rq->q, bio);
2930 blk_mq_rq_time_init(rq, 0);
2931 rq->cmd_flags = bio->bi_opf;
2932 INIT_LIST_HEAD(&rq->queuelist);
2936 * blk_mq_submit_bio - Create and send a request to block device.
2937 * @bio: Bio pointer.
2939 * Builds up a request structure from @q and @bio and send to the device. The
2940 * request may not be queued directly to hardware if:
2941 * * This request can be merged with another one
2942 * * We want to place request at plug queue for possible future merging
2943 * * There is an IO scheduler active at this queue
2945 * It will not queue the request if there is an error with the bio, or at the
2948 void blk_mq_submit_bio(struct bio *bio)
2950 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
2951 struct blk_plug *plug = blk_mq_plug(bio);
2952 const int is_sync = op_is_sync(bio->bi_opf);
2953 struct blk_mq_hw_ctx *hctx;
2954 unsigned int nr_segs = 1;
2958 bio = blk_queue_bounce(bio, q);
2961 * If the plug has a cached request for this queue, try use it.
2963 * The cached request already holds a q_usage_counter reference and we
2964 * don't have to acquire a new one if we use it.
2966 rq = blk_mq_peek_cached_request(plug, q, bio->bi_opf);
2968 if (unlikely(bio_queue_enter(bio)))
2972 if (unlikely(bio_may_exceed_limits(bio, &q->limits))) {
2973 bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
2977 if (!bio_integrity_prep(bio))
2980 if (blk_mq_attempt_bio_merge(q, bio, nr_segs))
2984 rq = blk_mq_get_new_requests(q, plug, bio, nr_segs);
2988 blk_mq_use_cached_rq(rq, plug, bio);
2991 trace_block_getrq(bio);
2993 rq_qos_track(q, rq, bio);
2995 blk_mq_bio_to_request(rq, bio, nr_segs);
2997 ret = blk_crypto_rq_get_keyslot(rq);
2998 if (ret != BLK_STS_OK) {
2999 bio->bi_status = ret;
3001 blk_mq_free_request(rq);
3005 if (op_is_flush(bio->bi_opf) && blk_insert_flush(rq))
3009 blk_add_rq_to_plug(plug, rq);
3014 if ((rq->rq_flags & RQF_USE_SCHED) ||
3015 (hctx->dispatch_busy && (q->nr_hw_queues == 1 || !is_sync))) {
3016 blk_mq_insert_request(rq, 0);
3017 blk_mq_run_hw_queue(hctx, true);
3019 blk_mq_run_dispatch_ops(q, blk_mq_try_issue_directly(hctx, rq));
3025 * Don't drop the queue reference if we were trying to use a cached
3026 * request and thus didn't acquire one.
3032 #ifdef CONFIG_BLK_MQ_STACKING
3034 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
3035 * @rq: the request being queued
3037 blk_status_t blk_insert_cloned_request(struct request *rq)
3039 struct request_queue *q = rq->q;
3040 unsigned int max_sectors = blk_queue_get_max_sectors(q, req_op(rq));
3041 unsigned int max_segments = blk_rq_get_max_segments(rq);
3044 if (blk_rq_sectors(rq) > max_sectors) {
3046 * SCSI device does not have a good way to return if
3047 * Write Same/Zero is actually supported. If a device rejects
3048 * a non-read/write command (discard, write same,etc.) the
3049 * low-level device driver will set the relevant queue limit to
3050 * 0 to prevent blk-lib from issuing more of the offending
3051 * operations. Commands queued prior to the queue limit being
3052 * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
3053 * errors being propagated to upper layers.
3055 if (max_sectors == 0)
3056 return BLK_STS_NOTSUPP;
3058 printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
3059 __func__, blk_rq_sectors(rq), max_sectors);
3060 return BLK_STS_IOERR;
3064 * The queue settings related to segment counting may differ from the
3067 rq->nr_phys_segments = blk_recalc_rq_segments(rq);
3068 if (rq->nr_phys_segments > max_segments) {
3069 printk(KERN_ERR "%s: over max segments limit. (%u > %u)\n",
3070 __func__, rq->nr_phys_segments, max_segments);
3071 return BLK_STS_IOERR;
3074 if (q->disk && should_fail_request(q->disk->part0, blk_rq_bytes(rq)))
3075 return BLK_STS_IOERR;
3077 ret = blk_crypto_rq_get_keyslot(rq);
3078 if (ret != BLK_STS_OK)
3081 blk_account_io_start(rq);
3084 * Since we have a scheduler attached on the top device,
3085 * bypass a potential scheduler on the bottom device for
3088 blk_mq_run_dispatch_ops(q,
3089 ret = blk_mq_request_issue_directly(rq, true));
3091 blk_account_io_done(rq, blk_time_get_ns());
3094 EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
3097 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
3098 * @rq: the clone request to be cleaned up
3101 * Free all bios in @rq for a cloned request.
3103 void blk_rq_unprep_clone(struct request *rq)
3107 while ((bio = rq->bio) != NULL) {
3108 rq->bio = bio->bi_next;
3113 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
3116 * blk_rq_prep_clone - Helper function to setup clone request
3117 * @rq: the request to be setup
3118 * @rq_src: original request to be cloned
3119 * @bs: bio_set that bios for clone are allocated from
3120 * @gfp_mask: memory allocation mask for bio
3121 * @bio_ctr: setup function to be called for each clone bio.
3122 * Returns %0 for success, non %0 for failure.
3123 * @data: private data to be passed to @bio_ctr
3126 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
3127 * Also, pages which the original bios are pointing to are not copied
3128 * and the cloned bios just point same pages.
3129 * So cloned bios must be completed before original bios, which means
3130 * the caller must complete @rq before @rq_src.
3132 int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
3133 struct bio_set *bs, gfp_t gfp_mask,
3134 int (*bio_ctr)(struct bio *, struct bio *, void *),
3137 struct bio *bio, *bio_src;
3142 __rq_for_each_bio(bio_src, rq_src) {
3143 bio = bio_alloc_clone(rq->q->disk->part0, bio_src, gfp_mask,
3148 if (bio_ctr && bio_ctr(bio, bio_src, data))
3152 rq->biotail->bi_next = bio;
3155 rq->bio = rq->biotail = bio;
3160 /* Copy attributes of the original request to the clone request. */
3161 rq->__sector = blk_rq_pos(rq_src);
3162 rq->__data_len = blk_rq_bytes(rq_src);
3163 if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) {
3164 rq->rq_flags |= RQF_SPECIAL_PAYLOAD;
3165 rq->special_vec = rq_src->special_vec;
3167 rq->nr_phys_segments = rq_src->nr_phys_segments;
3168 rq->ioprio = rq_src->ioprio;
3169 rq->write_hint = rq_src->write_hint;
3171 if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
3179 blk_rq_unprep_clone(rq);
3183 EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
3184 #endif /* CONFIG_BLK_MQ_STACKING */
3187 * Steal bios from a request and add them to a bio list.
3188 * The request must not have been partially completed before.
3190 void blk_steal_bios(struct bio_list *list, struct request *rq)
3194 list->tail->bi_next = rq->bio;
3196 list->head = rq->bio;
3197 list->tail = rq->biotail;
3205 EXPORT_SYMBOL_GPL(blk_steal_bios);
3207 static size_t order_to_size(unsigned int order)
3209 return (size_t)PAGE_SIZE << order;
3212 /* called before freeing request pool in @tags */
3213 static void blk_mq_clear_rq_mapping(struct blk_mq_tags *drv_tags,
3214 struct blk_mq_tags *tags)
3217 unsigned long flags;
3220 * There is no need to clear mapping if driver tags is not initialized
3221 * or the mapping belongs to the driver tags.
3223 if (!drv_tags || drv_tags == tags)
3226 list_for_each_entry(page, &tags->page_list, lru) {
3227 unsigned long start = (unsigned long)page_address(page);
3228 unsigned long end = start + order_to_size(page->private);
3231 for (i = 0; i < drv_tags->nr_tags; i++) {
3232 struct request *rq = drv_tags->rqs[i];
3233 unsigned long rq_addr = (unsigned long)rq;
3235 if (rq_addr >= start && rq_addr < end) {
3236 WARN_ON_ONCE(req_ref_read(rq) != 0);
3237 cmpxchg(&drv_tags->rqs[i], rq, NULL);
3243 * Wait until all pending iteration is done.
3245 * Request reference is cleared and it is guaranteed to be observed
3246 * after the ->lock is released.
3248 spin_lock_irqsave(&drv_tags->lock, flags);
3249 spin_unlock_irqrestore(&drv_tags->lock, flags);
3252 void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
3253 unsigned int hctx_idx)
3255 struct blk_mq_tags *drv_tags;
3258 if (list_empty(&tags->page_list))
3261 if (blk_mq_is_shared_tags(set->flags))
3262 drv_tags = set->shared_tags;
3264 drv_tags = set->tags[hctx_idx];
3266 if (tags->static_rqs && set->ops->exit_request) {
3269 for (i = 0; i < tags->nr_tags; i++) {
3270 struct request *rq = tags->static_rqs[i];
3274 set->ops->exit_request(set, rq, hctx_idx);
3275 tags->static_rqs[i] = NULL;
3279 blk_mq_clear_rq_mapping(drv_tags, tags);
3281 while (!list_empty(&tags->page_list)) {
3282 page = list_first_entry(&tags->page_list, struct page, lru);
3283 list_del_init(&page->lru);
3285 * Remove kmemleak object previously allocated in
3286 * blk_mq_alloc_rqs().
3288 kmemleak_free(page_address(page));
3289 __free_pages(page, page->private);
3293 void blk_mq_free_rq_map(struct blk_mq_tags *tags)
3297 kfree(tags->static_rqs);
3298 tags->static_rqs = NULL;
3300 blk_mq_free_tags(tags);
3303 static enum hctx_type hctx_idx_to_type(struct blk_mq_tag_set *set,
3304 unsigned int hctx_idx)
3308 for (i = 0; i < set->nr_maps; i++) {
3309 unsigned int start = set->map[i].queue_offset;
3310 unsigned int end = start + set->map[i].nr_queues;
3312 if (hctx_idx >= start && hctx_idx < end)
3316 if (i >= set->nr_maps)
3317 i = HCTX_TYPE_DEFAULT;
3322 static int blk_mq_get_hctx_node(struct blk_mq_tag_set *set,
3323 unsigned int hctx_idx)
3325 enum hctx_type type = hctx_idx_to_type(set, hctx_idx);
3327 return blk_mq_hw_queue_to_node(&set->map[type], hctx_idx);
3330 static struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
3331 unsigned int hctx_idx,
3332 unsigned int nr_tags,
3333 unsigned int reserved_tags)
3335 int node = blk_mq_get_hctx_node(set, hctx_idx);
3336 struct blk_mq_tags *tags;
3338 if (node == NUMA_NO_NODE)
3339 node = set->numa_node;
3341 tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
3342 BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
3346 tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3347 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3352 tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3353 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3355 if (!tags->static_rqs)
3363 blk_mq_free_tags(tags);
3367 static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
3368 unsigned int hctx_idx, int node)
3372 if (set->ops->init_request) {
3373 ret = set->ops->init_request(set, rq, hctx_idx, node);
3378 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
3382 static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set,
3383 struct blk_mq_tags *tags,
3384 unsigned int hctx_idx, unsigned int depth)
3386 unsigned int i, j, entries_per_page, max_order = 4;
3387 int node = blk_mq_get_hctx_node(set, hctx_idx);
3388 size_t rq_size, left;
3390 if (node == NUMA_NO_NODE)
3391 node = set->numa_node;
3393 INIT_LIST_HEAD(&tags->page_list);
3396 * rq_size is the size of the request plus driver payload, rounded
3397 * to the cacheline size
3399 rq_size = round_up(sizeof(struct request) + set->cmd_size,
3401 left = rq_size * depth;
3403 for (i = 0; i < depth; ) {
3404 int this_order = max_order;
3409 while (this_order && left < order_to_size(this_order - 1))
3413 page = alloc_pages_node(node,
3414 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
3420 if (order_to_size(this_order) < rq_size)
3427 page->private = this_order;
3428 list_add_tail(&page->lru, &tags->page_list);
3430 p = page_address(page);
3432 * Allow kmemleak to scan these pages as they contain pointers
3433 * to additional allocations like via ops->init_request().
3435 kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO);
3436 entries_per_page = order_to_size(this_order) / rq_size;
3437 to_do = min(entries_per_page, depth - i);
3438 left -= to_do * rq_size;
3439 for (j = 0; j < to_do; j++) {
3440 struct request *rq = p;
3442 tags->static_rqs[i] = rq;
3443 if (blk_mq_init_request(set, rq, hctx_idx, node)) {
3444 tags->static_rqs[i] = NULL;
3455 blk_mq_free_rqs(set, tags, hctx_idx);
3459 struct rq_iter_data {
3460 struct blk_mq_hw_ctx *hctx;
3464 static bool blk_mq_has_request(struct request *rq, void *data)
3466 struct rq_iter_data *iter_data = data;
3468 if (rq->mq_hctx != iter_data->hctx)
3470 iter_data->has_rq = true;
3474 static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx)
3476 struct blk_mq_tags *tags = hctx->sched_tags ?
3477 hctx->sched_tags : hctx->tags;
3478 struct rq_iter_data data = {
3482 blk_mq_all_tag_iter(tags, blk_mq_has_request, &data);
3486 static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu,
3487 struct blk_mq_hw_ctx *hctx)
3489 if (cpumask_first_and(hctx->cpumask, cpu_online_mask) != cpu)
3491 if (cpumask_next_and(cpu, hctx->cpumask, cpu_online_mask) < nr_cpu_ids)
3496 static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node)
3498 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3499 struct blk_mq_hw_ctx, cpuhp_online);
3501 if (!cpumask_test_cpu(cpu, hctx->cpumask) ||
3502 !blk_mq_last_cpu_in_hctx(cpu, hctx))
3506 * Prevent new request from being allocated on the current hctx.
3508 * The smp_mb__after_atomic() Pairs with the implied barrier in
3509 * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
3510 * seen once we return from the tag allocator.
3512 set_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3513 smp_mb__after_atomic();
3516 * Try to grab a reference to the queue and wait for any outstanding
3517 * requests. If we could not grab a reference the queue has been
3518 * frozen and there are no requests.
3520 if (percpu_ref_tryget(&hctx->queue->q_usage_counter)) {
3521 while (blk_mq_hctx_has_requests(hctx))
3523 percpu_ref_put(&hctx->queue->q_usage_counter);
3529 static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node)
3531 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3532 struct blk_mq_hw_ctx, cpuhp_online);
3534 if (cpumask_test_cpu(cpu, hctx->cpumask))
3535 clear_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3540 * 'cpu' is going away. splice any existing rq_list entries from this
3541 * software queue to the hw queue dispatch list, and ensure that it
3544 static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
3546 struct blk_mq_hw_ctx *hctx;
3547 struct blk_mq_ctx *ctx;
3549 enum hctx_type type;
3551 hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
3552 if (!cpumask_test_cpu(cpu, hctx->cpumask))
3555 ctx = __blk_mq_get_ctx(hctx->queue, cpu);
3558 spin_lock(&ctx->lock);
3559 if (!list_empty(&ctx->rq_lists[type])) {
3560 list_splice_init(&ctx->rq_lists[type], &tmp);
3561 blk_mq_hctx_clear_pending(hctx, ctx);
3563 spin_unlock(&ctx->lock);
3565 if (list_empty(&tmp))
3568 spin_lock(&hctx->lock);
3569 list_splice_tail_init(&tmp, &hctx->dispatch);
3570 spin_unlock(&hctx->lock);
3572 blk_mq_run_hw_queue(hctx, true);
3576 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
3578 if (!(hctx->flags & BLK_MQ_F_STACKING))
3579 cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3580 &hctx->cpuhp_online);
3581 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
3586 * Before freeing hw queue, clearing the flush request reference in
3587 * tags->rqs[] for avoiding potential UAF.
3589 static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags *tags,
3590 unsigned int queue_depth, struct request *flush_rq)
3593 unsigned long flags;
3595 /* The hw queue may not be mapped yet */
3599 WARN_ON_ONCE(req_ref_read(flush_rq) != 0);
3601 for (i = 0; i < queue_depth; i++)
3602 cmpxchg(&tags->rqs[i], flush_rq, NULL);
3605 * Wait until all pending iteration is done.
3607 * Request reference is cleared and it is guaranteed to be observed
3608 * after the ->lock is released.
3610 spin_lock_irqsave(&tags->lock, flags);
3611 spin_unlock_irqrestore(&tags->lock, flags);
3614 /* hctx->ctxs will be freed in queue's release handler */
3615 static void blk_mq_exit_hctx(struct request_queue *q,
3616 struct blk_mq_tag_set *set,
3617 struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
3619 struct request *flush_rq = hctx->fq->flush_rq;
3621 if (blk_mq_hw_queue_mapped(hctx))
3622 blk_mq_tag_idle(hctx);
3624 if (blk_queue_init_done(q))
3625 blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx],
3626 set->queue_depth, flush_rq);
3627 if (set->ops->exit_request)
3628 set->ops->exit_request(set, flush_rq, hctx_idx);
3630 if (set->ops->exit_hctx)
3631 set->ops->exit_hctx(hctx, hctx_idx);
3633 blk_mq_remove_cpuhp(hctx);
3635 xa_erase(&q->hctx_table, hctx_idx);
3637 spin_lock(&q->unused_hctx_lock);
3638 list_add(&hctx->hctx_list, &q->unused_hctx_list);
3639 spin_unlock(&q->unused_hctx_lock);
3642 static void blk_mq_exit_hw_queues(struct request_queue *q,
3643 struct blk_mq_tag_set *set, int nr_queue)
3645 struct blk_mq_hw_ctx *hctx;
3648 queue_for_each_hw_ctx(q, hctx, i) {
3651 blk_mq_exit_hctx(q, set, hctx, i);
3655 static int blk_mq_init_hctx(struct request_queue *q,
3656 struct blk_mq_tag_set *set,
3657 struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
3659 hctx->queue_num = hctx_idx;
3661 if (!(hctx->flags & BLK_MQ_F_STACKING))
3662 cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3663 &hctx->cpuhp_online);
3664 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
3666 hctx->tags = set->tags[hctx_idx];
3668 if (set->ops->init_hctx &&
3669 set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
3670 goto unregister_cpu_notifier;
3672 if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx,
3676 if (xa_insert(&q->hctx_table, hctx_idx, hctx, GFP_KERNEL))
3682 if (set->ops->exit_request)
3683 set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx);
3685 if (set->ops->exit_hctx)
3686 set->ops->exit_hctx(hctx, hctx_idx);
3687 unregister_cpu_notifier:
3688 blk_mq_remove_cpuhp(hctx);
3692 static struct blk_mq_hw_ctx *
3693 blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set,
3696 struct blk_mq_hw_ctx *hctx;
3697 gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY;
3699 hctx = kzalloc_node(sizeof(struct blk_mq_hw_ctx), gfp, node);
3701 goto fail_alloc_hctx;
3703 if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node))
3706 atomic_set(&hctx->nr_active, 0);
3707 if (node == NUMA_NO_NODE)
3708 node = set->numa_node;
3709 hctx->numa_node = node;
3711 INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
3712 spin_lock_init(&hctx->lock);
3713 INIT_LIST_HEAD(&hctx->dispatch);
3715 hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED;
3717 INIT_LIST_HEAD(&hctx->hctx_list);
3720 * Allocate space for all possible cpus to avoid allocation at
3723 hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *),
3728 if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8),
3729 gfp, node, false, false))
3733 spin_lock_init(&hctx->dispatch_wait_lock);
3734 init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);
3735 INIT_LIST_HEAD(&hctx->dispatch_wait.entry);
3737 hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp);
3741 blk_mq_hctx_kobj_init(hctx);
3746 sbitmap_free(&hctx->ctx_map);
3750 free_cpumask_var(hctx->cpumask);
3757 static void blk_mq_init_cpu_queues(struct request_queue *q,
3758 unsigned int nr_hw_queues)
3760 struct blk_mq_tag_set *set = q->tag_set;
3763 for_each_possible_cpu(i) {
3764 struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
3765 struct blk_mq_hw_ctx *hctx;
3769 spin_lock_init(&__ctx->lock);
3770 for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++)
3771 INIT_LIST_HEAD(&__ctx->rq_lists[k]);
3776 * Set local node, IFF we have more than one hw queue. If
3777 * not, we remain on the home node of the device
3779 for (j = 0; j < set->nr_maps; j++) {
3780 hctx = blk_mq_map_queue_type(q, j, i);
3781 if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
3782 hctx->numa_node = cpu_to_node(i);
3787 struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3788 unsigned int hctx_idx,
3791 struct blk_mq_tags *tags;
3794 tags = blk_mq_alloc_rq_map(set, hctx_idx, depth, set->reserved_tags);
3798 ret = blk_mq_alloc_rqs(set, tags, hctx_idx, depth);
3800 blk_mq_free_rq_map(tags);
3807 static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3810 if (blk_mq_is_shared_tags(set->flags)) {
3811 set->tags[hctx_idx] = set->shared_tags;
3816 set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs(set, hctx_idx,
3819 return set->tags[hctx_idx];
3822 void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3823 struct blk_mq_tags *tags,
3824 unsigned int hctx_idx)
3827 blk_mq_free_rqs(set, tags, hctx_idx);
3828 blk_mq_free_rq_map(tags);
3832 static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3833 unsigned int hctx_idx)
3835 if (!blk_mq_is_shared_tags(set->flags))
3836 blk_mq_free_map_and_rqs(set, set->tags[hctx_idx], hctx_idx);
3838 set->tags[hctx_idx] = NULL;
3841 static void blk_mq_map_swqueue(struct request_queue *q)
3843 unsigned int j, hctx_idx;
3845 struct blk_mq_hw_ctx *hctx;
3846 struct blk_mq_ctx *ctx;
3847 struct blk_mq_tag_set *set = q->tag_set;
3849 queue_for_each_hw_ctx(q, hctx, i) {
3850 cpumask_clear(hctx->cpumask);
3852 hctx->dispatch_from = NULL;
3856 * Map software to hardware queues.
3858 * If the cpu isn't present, the cpu is mapped to first hctx.
3860 for_each_possible_cpu(i) {
3862 ctx = per_cpu_ptr(q->queue_ctx, i);
3863 for (j = 0; j < set->nr_maps; j++) {
3864 if (!set->map[j].nr_queues) {
3865 ctx->hctxs[j] = blk_mq_map_queue_type(q,
3866 HCTX_TYPE_DEFAULT, i);
3869 hctx_idx = set->map[j].mq_map[i];
3870 /* unmapped hw queue can be remapped after CPU topo changed */
3871 if (!set->tags[hctx_idx] &&
3872 !__blk_mq_alloc_map_and_rqs(set, hctx_idx)) {
3874 * If tags initialization fail for some hctx,
3875 * that hctx won't be brought online. In this
3876 * case, remap the current ctx to hctx[0] which
3877 * is guaranteed to always have tags allocated
3879 set->map[j].mq_map[i] = 0;
3882 hctx = blk_mq_map_queue_type(q, j, i);
3883 ctx->hctxs[j] = hctx;
3885 * If the CPU is already set in the mask, then we've
3886 * mapped this one already. This can happen if
3887 * devices share queues across queue maps.
3889 if (cpumask_test_cpu(i, hctx->cpumask))
3892 cpumask_set_cpu(i, hctx->cpumask);
3894 ctx->index_hw[hctx->type] = hctx->nr_ctx;
3895 hctx->ctxs[hctx->nr_ctx++] = ctx;
3898 * If the nr_ctx type overflows, we have exceeded the
3899 * amount of sw queues we can support.
3901 BUG_ON(!hctx->nr_ctx);
3904 for (; j < HCTX_MAX_TYPES; j++)
3905 ctx->hctxs[j] = blk_mq_map_queue_type(q,
3906 HCTX_TYPE_DEFAULT, i);
3909 queue_for_each_hw_ctx(q, hctx, i) {
3911 * If no software queues are mapped to this hardware queue,
3912 * disable it and free the request entries.
3914 if (!hctx->nr_ctx) {
3915 /* Never unmap queue 0. We need it as a
3916 * fallback in case of a new remap fails
3920 __blk_mq_free_map_and_rqs(set, i);
3926 hctx->tags = set->tags[i];
3927 WARN_ON(!hctx->tags);
3930 * Set the map size to the number of mapped software queues.
3931 * This is more accurate and more efficient than looping
3932 * over all possibly mapped software queues.
3934 sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
3937 * Initialize batch roundrobin counts
3939 hctx->next_cpu = blk_mq_first_mapped_cpu(hctx);
3940 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
3945 * Caller needs to ensure that we're either frozen/quiesced, or that
3946 * the queue isn't live yet.
3948 static void queue_set_hctx_shared(struct request_queue *q, bool shared)
3950 struct blk_mq_hw_ctx *hctx;
3953 queue_for_each_hw_ctx(q, hctx, i) {
3955 hctx->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
3957 blk_mq_tag_idle(hctx);
3958 hctx->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
3963 static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set *set,
3966 struct request_queue *q;
3968 lockdep_assert_held(&set->tag_list_lock);
3970 list_for_each_entry(q, &set->tag_list, tag_set_list) {
3971 blk_mq_freeze_queue(q);
3972 queue_set_hctx_shared(q, shared);
3973 blk_mq_unfreeze_queue(q);
3977 static void blk_mq_del_queue_tag_set(struct request_queue *q)
3979 struct blk_mq_tag_set *set = q->tag_set;
3981 mutex_lock(&set->tag_list_lock);
3982 list_del(&q->tag_set_list);
3983 if (list_is_singular(&set->tag_list)) {
3984 /* just transitioned to unshared */
3985 set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
3986 /* update existing queue */
3987 blk_mq_update_tag_set_shared(set, false);
3989 mutex_unlock(&set->tag_list_lock);
3990 INIT_LIST_HEAD(&q->tag_set_list);
3993 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
3994 struct request_queue *q)
3996 mutex_lock(&set->tag_list_lock);
3999 * Check to see if we're transitioning to shared (from 1 to 2 queues).
4001 if (!list_empty(&set->tag_list) &&
4002 !(set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
4003 set->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
4004 /* update existing queue */
4005 blk_mq_update_tag_set_shared(set, true);
4007 if (set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
4008 queue_set_hctx_shared(q, true);
4009 list_add_tail(&q->tag_set_list, &set->tag_list);
4011 mutex_unlock(&set->tag_list_lock);
4014 /* All allocations will be freed in release handler of q->mq_kobj */
4015 static int blk_mq_alloc_ctxs(struct request_queue *q)
4017 struct blk_mq_ctxs *ctxs;
4020 ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL);
4024 ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx);
4025 if (!ctxs->queue_ctx)
4028 for_each_possible_cpu(cpu) {
4029 struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu);
4033 q->mq_kobj = &ctxs->kobj;
4034 q->queue_ctx = ctxs->queue_ctx;
4043 * It is the actual release handler for mq, but we do it from
4044 * request queue's release handler for avoiding use-after-free
4045 * and headache because q->mq_kobj shouldn't have been introduced,
4046 * but we can't group ctx/kctx kobj without it.
4048 void blk_mq_release(struct request_queue *q)
4050 struct blk_mq_hw_ctx *hctx, *next;
4053 queue_for_each_hw_ctx(q, hctx, i)
4054 WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list));
4056 /* all hctx are in .unused_hctx_list now */
4057 list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) {
4058 list_del_init(&hctx->hctx_list);
4059 kobject_put(&hctx->kobj);
4062 xa_destroy(&q->hctx_table);
4065 * release .mq_kobj and sw queue's kobject now because
4066 * both share lifetime with request queue.
4068 blk_mq_sysfs_deinit(q);
4071 struct request_queue *blk_mq_alloc_queue(struct blk_mq_tag_set *set,
4072 struct queue_limits *lim, void *queuedata)
4074 struct queue_limits default_lim = { };
4075 struct request_queue *q;
4078 q = blk_alloc_queue(lim ? lim : &default_lim, set->numa_node);
4081 q->queuedata = queuedata;
4082 ret = blk_mq_init_allocated_queue(set, q);
4085 return ERR_PTR(ret);
4089 EXPORT_SYMBOL(blk_mq_alloc_queue);
4092 * blk_mq_destroy_queue - shutdown a request queue
4093 * @q: request queue to shutdown
4095 * This shuts down a request queue allocated by blk_mq_alloc_queue(). All future
4096 * requests will be failed with -ENODEV. The caller is responsible for dropping
4097 * the reference from blk_mq_alloc_queue() by calling blk_put_queue().
4099 * Context: can sleep
4101 void blk_mq_destroy_queue(struct request_queue *q)
4103 WARN_ON_ONCE(!queue_is_mq(q));
4104 WARN_ON_ONCE(blk_queue_registered(q));
4108 blk_queue_flag_set(QUEUE_FLAG_DYING, q);
4109 blk_queue_start_drain(q);
4110 blk_mq_freeze_queue_wait(q);
4113 blk_mq_cancel_work_sync(q);
4114 blk_mq_exit_queue(q);
4116 EXPORT_SYMBOL(blk_mq_destroy_queue);
4118 struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set,
4119 struct queue_limits *lim, void *queuedata,
4120 struct lock_class_key *lkclass)
4122 struct request_queue *q;
4123 struct gendisk *disk;
4125 q = blk_mq_alloc_queue(set, lim, queuedata);
4129 disk = __alloc_disk_node(q, set->numa_node, lkclass);
4131 blk_mq_destroy_queue(q);
4133 return ERR_PTR(-ENOMEM);
4135 set_bit(GD_OWNS_QUEUE, &disk->state);
4138 EXPORT_SYMBOL(__blk_mq_alloc_disk);
4140 struct gendisk *blk_mq_alloc_disk_for_queue(struct request_queue *q,
4141 struct lock_class_key *lkclass)
4143 struct gendisk *disk;
4145 if (!blk_get_queue(q))
4147 disk = __alloc_disk_node(q, NUMA_NO_NODE, lkclass);
4152 EXPORT_SYMBOL(blk_mq_alloc_disk_for_queue);
4154 static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
4155 struct blk_mq_tag_set *set, struct request_queue *q,
4156 int hctx_idx, int node)
4158 struct blk_mq_hw_ctx *hctx = NULL, *tmp;
4160 /* reuse dead hctx first */
4161 spin_lock(&q->unused_hctx_lock);
4162 list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) {
4163 if (tmp->numa_node == node) {
4169 list_del_init(&hctx->hctx_list);
4170 spin_unlock(&q->unused_hctx_lock);
4173 hctx = blk_mq_alloc_hctx(q, set, node);
4177 if (blk_mq_init_hctx(q, set, hctx, hctx_idx))
4183 kobject_put(&hctx->kobj);
4188 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
4189 struct request_queue *q)
4191 struct blk_mq_hw_ctx *hctx;
4194 /* protect against switching io scheduler */
4195 mutex_lock(&q->sysfs_lock);
4196 for (i = 0; i < set->nr_hw_queues; i++) {
4198 int node = blk_mq_get_hctx_node(set, i);
4199 struct blk_mq_hw_ctx *old_hctx = xa_load(&q->hctx_table, i);
4202 old_node = old_hctx->numa_node;
4203 blk_mq_exit_hctx(q, set, old_hctx, i);
4206 if (!blk_mq_alloc_and_init_hctx(set, q, i, node)) {
4209 pr_warn("Allocate new hctx on node %d fails, fallback to previous one on node %d\n",
4211 hctx = blk_mq_alloc_and_init_hctx(set, q, i, old_node);
4212 WARN_ON_ONCE(!hctx);
4216 * Increasing nr_hw_queues fails. Free the newly allocated
4217 * hctxs and keep the previous q->nr_hw_queues.
4219 if (i != set->nr_hw_queues) {
4220 j = q->nr_hw_queues;
4223 q->nr_hw_queues = set->nr_hw_queues;
4226 xa_for_each_start(&q->hctx_table, j, hctx, j)
4227 blk_mq_exit_hctx(q, set, hctx, j);
4228 mutex_unlock(&q->sysfs_lock);
4231 static void blk_mq_update_poll_flag(struct request_queue *q)
4233 struct blk_mq_tag_set *set = q->tag_set;
4235 if (set->nr_maps > HCTX_TYPE_POLL &&
4236 set->map[HCTX_TYPE_POLL].nr_queues)
4237 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
4239 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
4242 int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
4243 struct request_queue *q)
4245 /* mark the queue as mq asap */
4246 q->mq_ops = set->ops;
4248 if (blk_mq_alloc_ctxs(q))
4251 /* init q->mq_kobj and sw queues' kobjects */
4252 blk_mq_sysfs_init(q);
4254 INIT_LIST_HEAD(&q->unused_hctx_list);
4255 spin_lock_init(&q->unused_hctx_lock);
4257 xa_init(&q->hctx_table);
4259 blk_mq_realloc_hw_ctxs(set, q);
4260 if (!q->nr_hw_queues)
4263 INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
4264 blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
4268 q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
4269 blk_mq_update_poll_flag(q);
4271 INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
4272 INIT_LIST_HEAD(&q->flush_list);
4273 INIT_LIST_HEAD(&q->requeue_list);
4274 spin_lock_init(&q->requeue_lock);
4276 q->nr_requests = set->queue_depth;
4278 blk_mq_init_cpu_queues(q, set->nr_hw_queues);
4279 blk_mq_add_queue_tag_set(set, q);
4280 blk_mq_map_swqueue(q);
4289 EXPORT_SYMBOL(blk_mq_init_allocated_queue);
4291 /* tags can _not_ be used after returning from blk_mq_exit_queue */
4292 void blk_mq_exit_queue(struct request_queue *q)
4294 struct blk_mq_tag_set *set = q->tag_set;
4296 /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */
4297 blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
4298 /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */
4299 blk_mq_del_queue_tag_set(q);
4302 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
4306 if (blk_mq_is_shared_tags(set->flags)) {
4307 set->shared_tags = blk_mq_alloc_map_and_rqs(set,
4310 if (!set->shared_tags)
4314 for (i = 0; i < set->nr_hw_queues; i++) {
4315 if (!__blk_mq_alloc_map_and_rqs(set, i))
4324 __blk_mq_free_map_and_rqs(set, i);
4326 if (blk_mq_is_shared_tags(set->flags)) {
4327 blk_mq_free_map_and_rqs(set, set->shared_tags,
4328 BLK_MQ_NO_HCTX_IDX);
4335 * Allocate the request maps associated with this tag_set. Note that this
4336 * may reduce the depth asked for, if memory is tight. set->queue_depth
4337 * will be updated to reflect the allocated depth.
4339 static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set *set)
4344 depth = set->queue_depth;
4346 err = __blk_mq_alloc_rq_maps(set);
4350 set->queue_depth >>= 1;
4351 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
4355 } while (set->queue_depth);
4357 if (!set->queue_depth || err) {
4358 pr_err("blk-mq: failed to allocate request map\n");
4362 if (depth != set->queue_depth)
4363 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
4364 depth, set->queue_depth);
4369 static void blk_mq_update_queue_map(struct blk_mq_tag_set *set)
4372 * blk_mq_map_queues() and multiple .map_queues() implementations
4373 * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
4374 * number of hardware queues.
4376 if (set->nr_maps == 1)
4377 set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues;
4379 if (set->ops->map_queues) {
4383 * transport .map_queues is usually done in the following
4386 * for (queue = 0; queue < set->nr_hw_queues; queue++) {
4387 * mask = get_cpu_mask(queue)
4388 * for_each_cpu(cpu, mask)
4389 * set->map[x].mq_map[cpu] = queue;
4392 * When we need to remap, the table has to be cleared for
4393 * killing stale mapping since one CPU may not be mapped
4396 for (i = 0; i < set->nr_maps; i++)
4397 blk_mq_clear_mq_map(&set->map[i]);
4399 set->ops->map_queues(set);
4401 BUG_ON(set->nr_maps > 1);
4402 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
4406 static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set,
4407 int new_nr_hw_queues)
4409 struct blk_mq_tags **new_tags;
4412 if (set->nr_hw_queues >= new_nr_hw_queues)
4415 new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *),
4416 GFP_KERNEL, set->numa_node);
4421 memcpy(new_tags, set->tags, set->nr_hw_queues *
4422 sizeof(*set->tags));
4424 set->tags = new_tags;
4426 for (i = set->nr_hw_queues; i < new_nr_hw_queues; i++) {
4427 if (!__blk_mq_alloc_map_and_rqs(set, i)) {
4428 while (--i >= set->nr_hw_queues)
4429 __blk_mq_free_map_and_rqs(set, i);
4436 set->nr_hw_queues = new_nr_hw_queues;
4441 * Alloc a tag set to be associated with one or more request queues.
4442 * May fail with EINVAL for various error conditions. May adjust the
4443 * requested depth down, if it's too large. In that case, the set
4444 * value will be stored in set->queue_depth.
4446 int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
4450 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
4452 if (!set->nr_hw_queues)
4454 if (!set->queue_depth)
4456 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
4459 if (!set->ops->queue_rq)
4462 if (!set->ops->get_budget ^ !set->ops->put_budget)
4465 if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
4466 pr_info("blk-mq: reduced tag depth to %u\n",
4468 set->queue_depth = BLK_MQ_MAX_DEPTH;
4473 else if (set->nr_maps > HCTX_MAX_TYPES)
4477 * If a crashdump is active, then we are potentially in a very
4478 * memory constrained environment. Limit us to 64 tags to prevent
4479 * using too much memory.
4481 if (is_kdump_kernel())
4482 set->queue_depth = min(64U, set->queue_depth);
4485 * There is no use for more h/w queues than cpus if we just have
4488 if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids)
4489 set->nr_hw_queues = nr_cpu_ids;
4491 if (set->flags & BLK_MQ_F_BLOCKING) {
4492 set->srcu = kmalloc(sizeof(*set->srcu), GFP_KERNEL);
4495 ret = init_srcu_struct(set->srcu);
4501 set->tags = kcalloc_node(set->nr_hw_queues,
4502 sizeof(struct blk_mq_tags *), GFP_KERNEL,
4505 goto out_cleanup_srcu;
4507 for (i = 0; i < set->nr_maps; i++) {
4508 set->map[i].mq_map = kcalloc_node(nr_cpu_ids,
4509 sizeof(set->map[i].mq_map[0]),
4510 GFP_KERNEL, set->numa_node);
4511 if (!set->map[i].mq_map)
4512 goto out_free_mq_map;
4513 set->map[i].nr_queues = set->nr_hw_queues;
4516 blk_mq_update_queue_map(set);
4518 ret = blk_mq_alloc_set_map_and_rqs(set);
4520 goto out_free_mq_map;
4522 mutex_init(&set->tag_list_lock);
4523 INIT_LIST_HEAD(&set->tag_list);
4528 for (i = 0; i < set->nr_maps; i++) {
4529 kfree(set->map[i].mq_map);
4530 set->map[i].mq_map = NULL;
4535 if (set->flags & BLK_MQ_F_BLOCKING)
4536 cleanup_srcu_struct(set->srcu);
4538 if (set->flags & BLK_MQ_F_BLOCKING)
4542 EXPORT_SYMBOL(blk_mq_alloc_tag_set);
4544 /* allocate and initialize a tagset for a simple single-queue device */
4545 int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set *set,
4546 const struct blk_mq_ops *ops, unsigned int queue_depth,
4547 unsigned int set_flags)
4549 memset(set, 0, sizeof(*set));
4551 set->nr_hw_queues = 1;
4553 set->queue_depth = queue_depth;
4554 set->numa_node = NUMA_NO_NODE;
4555 set->flags = set_flags;
4556 return blk_mq_alloc_tag_set(set);
4558 EXPORT_SYMBOL_GPL(blk_mq_alloc_sq_tag_set);
4560 void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
4564 for (i = 0; i < set->nr_hw_queues; i++)
4565 __blk_mq_free_map_and_rqs(set, i);
4567 if (blk_mq_is_shared_tags(set->flags)) {
4568 blk_mq_free_map_and_rqs(set, set->shared_tags,
4569 BLK_MQ_NO_HCTX_IDX);
4572 for (j = 0; j < set->nr_maps; j++) {
4573 kfree(set->map[j].mq_map);
4574 set->map[j].mq_map = NULL;
4579 if (set->flags & BLK_MQ_F_BLOCKING) {
4580 cleanup_srcu_struct(set->srcu);
4584 EXPORT_SYMBOL(blk_mq_free_tag_set);
4586 int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
4588 struct blk_mq_tag_set *set = q->tag_set;
4589 struct blk_mq_hw_ctx *hctx;
4596 if (q->nr_requests == nr)
4599 blk_mq_freeze_queue(q);
4600 blk_mq_quiesce_queue(q);
4603 queue_for_each_hw_ctx(q, hctx, i) {
4607 * If we're using an MQ scheduler, just update the scheduler
4608 * queue depth. This is similar to what the old code would do.
4610 if (hctx->sched_tags) {
4611 ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
4614 ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
4619 if (q->elevator && q->elevator->type->ops.depth_updated)
4620 q->elevator->type->ops.depth_updated(hctx);
4623 q->nr_requests = nr;
4624 if (blk_mq_is_shared_tags(set->flags)) {
4626 blk_mq_tag_update_sched_shared_tags(q);
4628 blk_mq_tag_resize_shared_tags(set, nr);
4632 blk_mq_unquiesce_queue(q);
4633 blk_mq_unfreeze_queue(q);
4639 * request_queue and elevator_type pair.
4640 * It is just used by __blk_mq_update_nr_hw_queues to cache
4641 * the elevator_type associated with a request_queue.
4643 struct blk_mq_qe_pair {
4644 struct list_head node;
4645 struct request_queue *q;
4646 struct elevator_type *type;
4650 * Cache the elevator_type in qe pair list and switch the
4651 * io scheduler to 'none'
4653 static bool blk_mq_elv_switch_none(struct list_head *head,
4654 struct request_queue *q)
4656 struct blk_mq_qe_pair *qe;
4658 qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY);
4662 /* q->elevator needs protection from ->sysfs_lock */
4663 mutex_lock(&q->sysfs_lock);
4665 /* the check has to be done with holding sysfs_lock */
4671 INIT_LIST_HEAD(&qe->node);
4673 qe->type = q->elevator->type;
4674 /* keep a reference to the elevator module as we'll switch back */
4675 __elevator_get(qe->type);
4676 list_add(&qe->node, head);
4677 elevator_disable(q);
4679 mutex_unlock(&q->sysfs_lock);
4684 static struct blk_mq_qe_pair *blk_lookup_qe_pair(struct list_head *head,
4685 struct request_queue *q)
4687 struct blk_mq_qe_pair *qe;
4689 list_for_each_entry(qe, head, node)
4696 static void blk_mq_elv_switch_back(struct list_head *head,
4697 struct request_queue *q)
4699 struct blk_mq_qe_pair *qe;
4700 struct elevator_type *t;
4702 qe = blk_lookup_qe_pair(head, q);
4706 list_del(&qe->node);
4709 mutex_lock(&q->sysfs_lock);
4710 elevator_switch(q, t);
4711 /* drop the reference acquired in blk_mq_elv_switch_none */
4713 mutex_unlock(&q->sysfs_lock);
4716 static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
4719 struct request_queue *q;
4721 int prev_nr_hw_queues = set->nr_hw_queues;
4724 lockdep_assert_held(&set->tag_list_lock);
4726 if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids)
4727 nr_hw_queues = nr_cpu_ids;
4728 if (nr_hw_queues < 1)
4730 if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues)
4733 list_for_each_entry(q, &set->tag_list, tag_set_list)
4734 blk_mq_freeze_queue(q);
4736 * Switch IO scheduler to 'none', cleaning up the data associated
4737 * with the previous scheduler. We will switch back once we are done
4738 * updating the new sw to hw queue mappings.
4740 list_for_each_entry(q, &set->tag_list, tag_set_list)
4741 if (!blk_mq_elv_switch_none(&head, q))
4744 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4745 blk_mq_debugfs_unregister_hctxs(q);
4746 blk_mq_sysfs_unregister_hctxs(q);
4749 if (blk_mq_realloc_tag_set_tags(set, nr_hw_queues) < 0)
4753 blk_mq_update_queue_map(set);
4754 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4755 blk_mq_realloc_hw_ctxs(set, q);
4756 blk_mq_update_poll_flag(q);
4757 if (q->nr_hw_queues != set->nr_hw_queues) {
4758 int i = prev_nr_hw_queues;
4760 pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
4761 nr_hw_queues, prev_nr_hw_queues);
4762 for (; i < set->nr_hw_queues; i++)
4763 __blk_mq_free_map_and_rqs(set, i);
4765 set->nr_hw_queues = prev_nr_hw_queues;
4768 blk_mq_map_swqueue(q);
4772 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4773 blk_mq_sysfs_register_hctxs(q);
4774 blk_mq_debugfs_register_hctxs(q);
4778 list_for_each_entry(q, &set->tag_list, tag_set_list)
4779 blk_mq_elv_switch_back(&head, q);
4781 list_for_each_entry(q, &set->tag_list, tag_set_list)
4782 blk_mq_unfreeze_queue(q);
4784 /* Free the excess tags when nr_hw_queues shrink. */
4785 for (i = set->nr_hw_queues; i < prev_nr_hw_queues; i++)
4786 __blk_mq_free_map_and_rqs(set, i);
4789 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
4791 mutex_lock(&set->tag_list_lock);
4792 __blk_mq_update_nr_hw_queues(set, nr_hw_queues);
4793 mutex_unlock(&set->tag_list_lock);
4795 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
4797 static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
4798 struct io_comp_batch *iob, unsigned int flags)
4800 long state = get_current_state();
4804 ret = q->mq_ops->poll(hctx, iob);
4806 __set_current_state(TASK_RUNNING);
4810 if (signal_pending_state(state, current))
4811 __set_current_state(TASK_RUNNING);
4812 if (task_is_running(current))
4815 if (ret < 0 || (flags & BLK_POLL_ONESHOT))
4818 } while (!need_resched());
4820 __set_current_state(TASK_RUNNING);
4824 int blk_mq_poll(struct request_queue *q, blk_qc_t cookie,
4825 struct io_comp_batch *iob, unsigned int flags)
4827 struct blk_mq_hw_ctx *hctx = xa_load(&q->hctx_table, cookie);
4829 return blk_hctx_poll(q, hctx, iob, flags);
4832 int blk_rq_poll(struct request *rq, struct io_comp_batch *iob,
4833 unsigned int poll_flags)
4835 struct request_queue *q = rq->q;
4838 if (!blk_rq_is_poll(rq))
4840 if (!percpu_ref_tryget(&q->q_usage_counter))
4843 ret = blk_hctx_poll(q, rq->mq_hctx, iob, poll_flags);
4848 EXPORT_SYMBOL_GPL(blk_rq_poll);
4850 unsigned int blk_mq_rq_cpu(struct request *rq)
4852 return rq->mq_ctx->cpu;
4854 EXPORT_SYMBOL(blk_mq_rq_cpu);
4856 void blk_mq_cancel_work_sync(struct request_queue *q)
4858 struct blk_mq_hw_ctx *hctx;
4861 cancel_delayed_work_sync(&q->requeue_work);
4863 queue_for_each_hw_ctx(q, hctx, i)
4864 cancel_delayed_work_sync(&hctx->run_work);
4867 static int __init blk_mq_init(void)
4871 for_each_possible_cpu(i)
4872 init_llist_head(&per_cpu(blk_cpu_done, i));
4873 for_each_possible_cpu(i)
4874 INIT_CSD(&per_cpu(blk_cpu_csd, i),
4875 __blk_mq_complete_request_remote, NULL);
4876 open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
4878 cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
4879 "block/softirq:dead", NULL,
4880 blk_softirq_cpu_dead);
4881 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
4882 blk_mq_hctx_notify_dead);
4883 cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online",
4884 blk_mq_hctx_notify_online,
4885 blk_mq_hctx_notify_offline);
4888 subsys_initcall(blk_mq_init);